What drives your depression? Manic Depression, perhaps? One moment you feel very good, the next moment you feel like crap.
I used to be very depressed, about a year and a half ago, at school. I never thought I'd get through all the crap, but I did. I still get depressed now, but nowhere near as much.
I know how it feels, just stay true to yourself and take any criticisms and hardships into context, think of a rational solution, and don't take crap from anybody. Do what you like doing best when you feel sad.
I hope you feel better soon enough. 
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Lalalalai.... I'll cut you up!