Feedback on School. :(

I try to do better in school, but yet I do worse. I don't know what else to do right now... my mind is so occupied that I can't even do well. My AP English teacher screwed up my grade like really badly and my AP US class is going bad... because I don't know how to take tests well. I'm doing terribly... and I don't have enough classes to bring my grade back up.. AP Calculus, I'm failing in those exams that she gives us and I don't know what to do. I have SAT prep on Sundays and Mondays from 7-10. I'm exhausted. I just want to sleep and never wake up. I'm so sad. :/