Hit a plateau-- if you've stopped losing weight, then?

I have been on a plateau of weight loss since August 2010. Of course, I was eating ice cream every so often and having a couple of drinks here and there, but I otherwise eat very healthy and nutritious. Recently, I have buckled down, I am strictly eating good things, and am limiting my calorie intake to about 15-1600/a day. Plus, I have been working out hard everyday. It's been a week and a half since I have really been on a strict diet, but I am still seeing the same weight! Does my body not want me to lose anymore? I am 5'6 and weigh 157-160 (fluctuates everyday). I don't know what else to do!