Okay its not good that you hardly eat. If you hardly it everyday its a good chance of be coming anorexic and you don't wanna get into that. Why not try looking up some healthy recipes you can try online or ask your mom to help you out and be sure to stay away from all that sweet stuff.
And if its because you're worried about what people think of you at school don't worry about what they think. Sometimes they can just be mean and shallow. You're fine! Oh and remember to drink lots of water while exercising.