Maybe you are gaining muscle, and muscle weighs more than fat. I have heard that you should alternate with your calorie intake to kind of trick your body. For instance if you eat 1000 calories one day try eating 1200 calories the next day and keep alternating it so your body doesn't get used to the same 1000 calories. Have you ever watched Biggest Loser? I remember watching an episode where one of the girls ( I think Ali) wasn't eating much because she thought that if she ate less she would lose more, the trainer (jillian) said that because she's exercising you need to eat more so that your body has more to burn while your exercising or something like that. She upped her caloric intake and continued to exercise and she lost more weight that way, I think maybe you should up your calorie intake by at least 100 or 200. Good luck, 8lbs in 2 weeks is great though!!!