Try to talk with a parent or both about what you have been going through. They should be able to help and want the best for you. If that is impossible, go to a trusted teacher, clergyman, school counselor, or someone else in a position to listen and help you. Help is available. Also, in addition, I recommend professional counseling for you to be able to talk out these issues on a continuing basis until you feel much better.
Okay so, I'm sorry if this is too late, but I just found the page and read what you post. I'm sorry you are going through all of those awful things. I completely understand what you say about your parents because we are in the same boat. I'm 15 and I don't know if I'm depressed or what, but I feel the same way that you do. I can´t tell my parents because they would either not believe me or freak out.
I wish I could tell you that everything is going to be fine, but I'm not that kind of person, and I don't know that. Maybe you should try talking with a close friend, or with an older sibling. If you don't want to talk, or can't talk about it, maybe trying to find a hobby would be good for you. When I´m feeling down or anxious I play some music, draw, or do something that will distract me.
Good luck and stay strong
(And, about the person that died... I don´t know if this is the most adequate thing to say, and I'm really sorry if I hurt you... But honestly, I think that that person is now in a better place. Try to think that, and please don't blame yourself or anything like that, because it wasn't your fault)