Have you seen a dietician? You might not be eating enough and developing a set-point metabolism. When I tried to lose a few pounds(I weighed my full term pregnancy weight, while not pregnant), I found that I had to have a book tell me exactly what TO eat, not-what not to eat. It was the Curves diet book if that helps. I did lose the weight, but I had to learn to incorporate more lean protein into my diet than what I was getting.