Try cutting out 500 calories per day to lose 1 pound a week. It's safe to lose 1 to 2 pounds per week. Add in a lot of cardio like running and swimming, etc. and weight train about 3x per week if you want. You can do this!! Switch all sodas you are drinking to diet, eliminate all sugars, junk foods, and sweets, lower your carbs (reduce intake of breads/pasta) and drink plenty of water as well as take a multivitamin! The process will be gradual but eventually you will begin to see results. If you do this religiously over the summer you could lose a lot. If you are still having trouble maybe you could visit your doctor because it may be something internally, like your thyroid, for example that is keeping you from losing it. Just hang in there!! Don't become bulimic or anorexic, it really affects your heart and much of the weight lost would be muscle or water, leaving you tired and weak. I have a friend with ana and bulimia and she is now hospitalized and very sick, with many heart problems, pretty much dying.

Good luck and you can do this!!