I remember reading a book in middle school about a young girl (pretty sure her name was Mabel) who followed a cat to a pond out in the woods. Something (can’t remember what) pulled her into the lake to the other side. She made friends with a guy who had a pumpkin for a head. That’s all I can really remember besides that it was a series.
May Bird and the Ever After by Jodi Lynn Anderson.
Most people aren't very comfortable in the woods, but the woods of Briery Swamp fit May Bird like a fuzzy mitten. There, she is safe from school and the taunts and teases of kids who don't understand her. Hidden in the trees, May is a warrior princess, and her cat, Somber Kitty, is her brave guardian.
Then May falls into the lake. A ghost named Pumpkin (with a pumpkin head) is her guardian and follows her into the lake to help her through.
When she crawls out, May finds herself in a world that most certainly does not feel like a fuzzy mitten. In fact it is a place few living people have ever seen. Here, towns glow blue beneath zipping stars and the people -- people? -- walk through walls. Here the Book of the Dead holds the answers to everything in the universe. And here, if May is discovered, the horrifyingly evil Bo Cleevil will turn her into nothing.