How do I help myself with depression?

I recently starting having depression problems; I have to farce myself to eat, I can hardly stand to be around sharp objects because of how badly I want to hurt myself. So my parents are at court against each other and after years of being afraid of seeing my father again the courts finally decided that I never have to see him again. I should be happy, but court expenses have us in debt and I am more worried about my situation than I was before. I am going to be starting High School next year, and I am really scared. My friends in school are starting to experiment with their life's and are doing stupid things like smoking and drinking, so I decided I didn't want to hang around them anymore. Now I am pretty much alone and I have nobody I can talk to about how I feel. My family is under too much stress and I don't trust any of my former friends. Everybody in my house is yelling at each other and everybody is at each others throats. My room had to be taken over so that my big sister can move back in because she cant afford an apartment anymore and I have nowhere I can go to just cry. I feel so trapped! Every time I look in a mirror I almost want to cry because I just cant appreciate myself at all, and I'm too scared to go outside or someplace public. Even when I did hang out with m,y friends, they had never really listened to any of my personal problems and they always say that they hate each other. They mean it as a joke, but it really hurts. I try to write and draw how I feel but I cant think of anything to put on the paper. I used to really be into writing my own music and piano playing, but I cant find the motivation to do anything but pace in our kitchen. I know I wouldn't be strong enough to do it, but I cant stop thinking about suicide. My grades are dropping drastically, even though we only have one more week of school, and I'm not sure I can make it through these last few days. Any advice on how I can help myself, or any information about depression would be helpful.