I have a fear of getting fat?

I'm 16, 5'9" and I weigh 115 pounds, whenever I would finish eating I felt guilty because I really don't want to gain any weight but I want to lose weight so I started trying to make myself throw up (I know it's unhealthy)...but I couldn't anyways, so instead I stopped eating most of the time so now I eat less then 200 calories a day, anyways I want to be healthy and eat food but I still want to lose 15 pounds so I'm not as fat because I don't want to be able to grab stomach fat at all cuz it's gross, so I need advice on what to eat so I can lose 15 pounds fast ... And what exercises I can do (besides yoga and running/walking cuz I already do that)