pre-a level stress

I'm 17 years old and have had IBS for the last 3 months. I'm getting frustrated because im writing down what i eat but i can't tell whats causing the flatulence, constipation or cramping. I've tried exercising and it doesn't help much. I get embarrassed being in public areas and don't like to be stuck in a room with anyone :(. Sometimes I don't even leave my house because i just don't want to be around my friends and family and be the farting freak.