急！急！急！英语求助信！

Dear Mr Wang,
This is Li Hua. Remember me? How are you now? I need your help because I find I'm not very used to the high school life.
We have nine subjects in all. Every day I have to spend at least three to four hours doing my homework, so there is little time left for activities after class. I hardly have any time to do what I want to. Besides, I sometimes feel sleepy in class because I don't have enough sleep. The great pressure of/from exams and the high expectations from my parents often make me even more tired.
The biggest problem that I meet now is my maths study, which is much more difficult than that in junior middle school. I don't know how to improve it. So I hope I could get some advice from you.
All the best.
Yours truly,
Li Hua