You can eat less sugar; cut out crisps and fat. Eat lots of fruit and salads, yogurts, healthy food. Walk and exercise daily. Find a friend or ask yr mom to walk with you if you don't like to walk alone. Stay away from TV of things that remind you of food or eat healthy snacks like carrots, cucumbers, bananas. If you still feel worried, go to your doctor and he/ she will put you on a healthy diet/ eating plan.
Please don't let these people get you down as they are NOT true friends. Good friends help& advise you; they don't call you fat and make you feel bad about yourself. Many people get fat from time to time. So what? It only matters from a HEALTH viewpoint and so you feel GOOD about YOURSELF.
Try to make new friends who will treat you better. Stay away from these people and don't worry about what they think; they're cruel& immature. Once you feel better about yourself, you will attract better friends: Friends who like the INNER you and are not critical.
You're too young to date. When the time is right, boys will approach you on their own. Focus on your health and your school and making better friends. Romance will come on its own when you're older and the time is right and you feel good about yourself- whatever your weight.