Weight Lose help. anyone whos lost alot of weight?

now i know almost every single girl in the world has this problem but please take my case seriously. I am 14 and im not fat, im not one of thoes people who says there fat when there a tooth pick, but i have a tummy that is embarrasing to dhow in a bathing suit. My parents tell me everyday i am overweight, and they won't let me wear cute clothes untill i get a flat tummy (i live in the tropics so i cnt hide anything!) anyway i know excersize and healthy eating is the key, but i am forced by my school to buy lunch, which isn't too healthy, and at dinner we eat good meals (chicken, rice, and peas usually) i want to exercize but i honestly hate it more then anything. the temperature outside is around 95 and excersing makes me grumpy and sweaty for the rest of the day. My parents signed me up for excersize cles but the ntook me out because they couldn't pay. I suffer from depression and use food to get me through it (and dont say food doesnt work cause nutella can make anyone happy) so anyone whos been in my situation and has lost the fat can u help? Thnks so much.