I read a book in seventh grade, that I think was released in 2005.
The main character is a girl who lived on her family farm, and she could see this ghost boy.
One day this tunic-wearing man comes in and tells her that there's a place where she'd be more accepted and where she can learn about her powers. She goes and some stuff happens then she finds out that the tunic clad man was using her to harvest the power of the unicorns and she fought him.
I cannot remember the title of this book to save my life, please help.
The book cover was blue, and there were grey blobs (I don't remember what the blobs were though).