How do you cure depression?

I've tried talking, reading, and even praying, but nothing seems to work. I'm 18, and am supposed to be a high-flying achiever. I try to be but I keep putting myself down, nothing I do seems good enough and anything near perfect I don't deserve. My father tells me am 'nothing special' and doesn't get the fact that I self-mutilate and am suicidal( I have been like this since I was 8). Mum freaks out when I try and talk to a counsellour. She thinks its stupid and unnecessary and makes her look like a bad parents. I don't know how to tell them its because I've been molested as a child and when I was 16 (regularly by my clmate) I'm scared because its manifesting in everything I do. The next time I try and kill mysef, am scared I'll do it.HELP!