Dear Capitolina Bonifacia,
You should consult a nutritionist, so he can give you more advice of how to start and finish a diet. You should went to a gym, so you can make more exercise and get more thin.
If you aren’t interested in get more thin you should consult a psychologist so he or she resolve your emotional problem. You also should talk to your teachers or your school director to tell your classmates stop bullying you.
When you feel more happy and confident, and when your problem be solved, write another letter and tell me everything that happened to you since then.