HELP? I am going to p out from this stress.?

Okay, I am only (well not even yet) 17 but I am having a hard time functioning in life. I got removed from my high school because I had poor attendance. I didn't go because I seriously feared being looked at. (I felt obese even though I am not even overweight) I didn't like leaving my house to do anything let alone go to school. I also had drug abuse induced paranoia and auditory hallucinations. Now I am a lot less paranoid and I can leave the house but I have to wait till September to register again. Anyways the complaint is whenever I think about anything remotely difficult/scary I cry and/or I feel like I cannot breathe. I don't use drugs anymore but all this stress is pushing me to want to again. I have few chances left with my family (I probably actually have none) so I really don't want to blow it. I've been trying to eat healthy and exercise to help me cope with life and it is working but not enough. What can I do? I love living but I am worried if one more little thing in my life goes wrong I am going to break. (My family has a history of mental illness and suicide - on both sides- )