I'm so down

I feel so down these days
i dont know why
really..

is it because of the "pre-examination depression"??
hahax
i dont know why every time before the exam, i feel very bad
my mood become very bad

i tried to cheer up
tried no to think about the negative things
i tried a lot of ways to cheer me up
but i failed..

Haiz
i still emoing
until ee cing noticed that
she asked me "yan er,do you have any trouble?"
then i answer "ya,actually.."
this was the same problem since form 4
why i still cant solve it?
i want to know the causes of this problem
really
i need to know it and solve it as soon as possible
i scare my future will be affected
i scare this and that
a lot of worries...

anybody can help me??
please tell me the way to solve my problem
please....