My boyfriend has been thinking of this book he read in high school, but he can't remember the title. It was written in the point of view of a girl in a classroom. She was writing for an assignment, but the teacher wasn't reading her diary entries. The girl lived with her mom and younger sister. They had a lot of troubles going on and she had to take a job at Burger King to help out. Near the end, the mom ran away with the dad and the girl had to take care of her younger sister by herself.
Any ideas?