According to this Goodreads question, it's Fate Worse Than Death and More Fright with a Bite, which was a 1996 book by Troll Communications.

Another story was about a hypochondriac girl who is invited to a costume party and during a power outage is bitten by what she thinks is a vampire (I remember she made her own costume and it was Marie Antoinette). Convinced she's becoming a vampire, she develops all the symptoms and attempts to fly out her bedroom window to go to her "master". She fails and breaks her leg (or arm?) and as her parents are driving her home from the hospital, she looks out the window, sees the moon, and howls all while canine-like hairs are sprouting out of her arms. It ends there with the the understanding that she's been bitten by a werewolf, not a vampire. I think that may have been the only non-vampire story.

....

The last story in the book was about a family on a road trip. It's late and the family is hungry. One son convinces his dad to not worry about making good time and to pull off at the first exit for dinner. He does and it's an exit not listed on their map. The restaurant they go to is for vampires and they serve blood. When the vampires realize that they have humans in their midst, one of them goes crazy and tries to attack the family. The others stop him, saying that they don't feed like this anymore, and the family leaves. As the family gets back on the highway, they hear a loud thud on the roof of their car. The son, who got his dad to stop in the first place, says something along the lines of "I think we should just keep driving all night, Dad". And that's the end of the story.

They found it by searching the Google Book.

The other story (about the vampire looking for the long-lost love) seems to be referenced in the summary here (bolding mine):

Be prepared to be scared! — Two kids vow to be friends forever -- even after one of them becomes a vampire. — A beautiful girl is being stalked by a vampire who's been waiting for her -- for more than three hundred years! — Ready to sink your teeth into terror? You'll love what's on the menu in Bites, a spine-tingling collection of stories about vampires, the legendary rulers of the night.

According to this Goodreads question, it's Fate Worse Than Death and More Fright with a Bite, which was a 1996 book by Troll Communications.

Another story was about a hypochondriac girl who is invited to a costume party and during a power outage is bitten by what she thinks is a vampire (I remember she made her own costume and it was Marie Antoinette). Convinced she's becoming a vampire, she develops all the symptoms and attempts to fly out her bedroom window to go to her "master". She fails and breaks her leg (or arm?) and as her parents are driving her home from the hospital, she looks out the window, sees the moon, and howls all while canine-like hairs are sprouting out of her arms. It ends there with the the understanding that she's been bitten by a werewolf, not a vampire. I think that may have been the only non-vampire story.

....

The last story in the book was about a family on a road trip. It's late and the family is hungry. One son convinces his dad to not worry about making good time and to pull off at the first exit for dinner. He does and it's an exit not listed on their map. The restaurant they go to is for vampires and they serve blood. When the vampires realize that they have humans in their midst, one of them goes crazy and tries to attack the family. The others stop him, saying that they don't feed like this anymore, and the family leaves. As the family gets back on the highway, they hear a loud thud on the roof of their car. The son, who got his dad to stop in the first place, says something along the lines of "I think we should just keep driving all night, Dad". And that's the end of the story.

They found it by searching the Google Book.

The other story (about the vampire looking for the long-lost love) seems to be referenced in the summary here (bolding mine):

Be prepared to be scared! — Two kids vow to be friends forever -- even after one of them becomes a vampire. — A beautiful girl is being stalked by a vampire who's been waiting for her -- for more than three hundred years! — Ready to sink your teeth into terror? You'll love what's on the menu in Bites, a spine-tingling collection of stories about vampires, the legendary rulers of the night.

I found it by searching for short story hypochondriac vampire on Google.

According to this Goodreads question, it's Fate Worse Than Death and More Fright with a Bite, which was a 1996 book by Troll Communications.

Another story was about a hypochondriac girl who is invited to a costume party and during a power outage is bitten by what she thinks is a vampire (I remember she made her own costume and it was Marie Antoinette). Convinced she's becoming a vampire, she develops all the symptoms and attempts to fly out her bedroom window to go to her "master". She fails and breaks her leg (or arm?) and as her parents are driving her home from the hospital, she looks out the window, sees the moon, and howls all while canine-like hairs are sprouting out of her arms. It ends there with the the understanding that she's been bitten by a werewolf, not a vampire. I think that may have been the only non-vampire story.

....

The last story in the book was about a family on a road trip. It's late and the family is hungry. One son convinces his dad to not worry about making good time and to pull off at the first exit for dinner. He does and it's an exit not listed on their map. The restaurant they go to is for vampires and they serve blood. When the vampires realize that they have humans in their midst, one of them goes crazy and tries to attack the family. The others stop him, saying that they don't feed like this anymore, and the family leaves. As the family gets back on the highway, they hear a loud thud on the roof of their car. The son, who got his dad to stop in the first place, says something along the lines of "I think we should just keep driving all night, Dad". And that's the end of the story.

They found it by searching the Google Book.

According to this Goodreads question, it's Fate Worse Than Death and More Fright with a Bite, which was a 1996 book by Troll Communications.

Another story was about a hypochondriac girl who is invited to a costume party and during a power outage is bitten by what she thinks is a vampire (I remember she made her own costume and it was Marie Antoinette). Convinced she's becoming a vampire, she develops all the symptoms and attempts to fly out her bedroom window to go to her "master". She fails and breaks her leg (or arm?) and as her parents are driving her home from the hospital, she looks out the window, sees the moon, and howls all while canine-like hairs are sprouting out of her arms. It ends there with the the understanding that she's been bitten by a werewolf, not a vampire. I think that may have been the only non-vampire story.

....

The last story in the book was about a family on a road trip. It's late and the family is hungry. One son convinces his dad to not worry about making good time and to pull off at the first exit for dinner. He does and it's an exit not listed on their map. The restaurant they go to is for vampires and they serve blood. When the vampires realize that they have humans in their midst, one of them goes crazy and tries to attack the family. The others stop him, saying that they don't feed like this anymore, and the family leaves. As the family gets back on the highway, they hear a loud thud on the roof of their car. The son, who got his dad to stop in the first place, says something along the lines of "I think we should just keep driving all night, Dad". And that's the end of the story.

They found it by searching the Google Book.

The other story (about the vampire looking for the long-lost love) seems to be referenced in the summary here (bolding mine):

Be prepared to be scared! — Two kids vow to be friends forever -- even after one of them becomes a vampire. — A beautiful girl is being stalked by a vampire who's been waiting for her -- for more than three hundred years! — Ready to sink your teeth into terror? You'll love what's on the menu in Bites, a spine-tingling collection of stories about vampires, the legendary rulers of the night.