Anybody know whats wrong with my stomach?

Im 16 and im really really depressed right now for many reasons. My depression and other things make me really stressed out and i think the stress is what's causing my stomach to hurt. I usually get sick for a few hours every day or sometimes the whole day. Yet whenever I try to be happy and ignore the problems or take medicine i still get sick. My body rejects lots of medicines and ive started eating significantly less than i used to but i still eat whole healthy meals. It usually ends up with me having severe stomach aches, diarrhea, and throwin up a lot. Anything that could help would be much appreciated.