Depression Help?

I know it's not true, but sometimes i doubt that god exists because my past was painfull with my parentsy breaking up and being abused by my mothers ex-boyfreind, who had my little sister with my mom, and he threatens my family constantly to kill us. My dad has smoked pot for years. (He doesn't know I know and he's not a bad person.) Now, i'm a 13 year old kid who lives with my grandparents and brother and we're swimming in financial debt. At least 5 times i've had to move and leave my friends to never see them again and my house is for sale again. I've almost got killed in a drive by shooting also. My past sucked and so does my present. Now it seems as though my future isn't going to be much better either. I'm depressed all the time and it's hard not to let my friends see it. I don't know what to do. Help!