Dear Ms.X,
I'm very glad to write to you.
As the exam is around the corner,I feel so worried about it.Duo to the heavy study duty and lack of doing sports,I can not have enough sleep so that I feel very tired in the classroom.Besides,my classmates and I are too busy to communicate with each other which makes me feel more depressed.When I am at home,watching TV,surfing the Internet,listening to the music and so on are forbidden by my parents.Therefore,I hope that you can give me some advice or teach me how to handle these matters.
I am looking forward to hearing from you.
Yours
XX（人名）