How are you trying to lose weight? Make sure your eating enough. When you start to skip meals it messes up your metabolism which burns calories. Also when you don't eat often enough your body starts storing what food you do it as fat. Trust me, ...... OH and don't eat too many nectarines! As in too many I mean like 5 a day :p that will also make you gain weight. But eat nectarines there good for you!!!! lots of vitamins! Just not 5 a day ....... thats a little too much sugar .... ..... ..... I love nectarines :p
you can't rush results, as the miracle worker in the princess bride says "if you rush the miracle man, you get rotten miracles), just keep working at it and be patient. It's also possible that you are losing fat but gaining muscle, which would result in a leaner and slimmer figure, but a low loss, or slight gain in total body weight, because muscle is heavier than fat.
how fast is fast enough? there's no secret to weight loss, and 1 to 2 lbs. a week at most is how you'll get the healthiest and longest lasting results. you didn't gain what you want to lose over night and you shouldn't expect to lose it that fast either. be safe, be healthy, and you'll be happy. good luck.