You seem to be losing weight pretty easily, Nickie, considering you lose even when you don't stick to the program so well. So I don't think your metabolism is an issue. I had trouble losing even while ON the program, because I'd already been eating only about 1,000 calories per day (and low-carb) before Medifast.
Not that I want to discourage anyone from checking it out as a maintenance plan. Burn the Fat, Feed the Muscle by Tom Venuto. Online only (no actual bookstore-type book; it's strictly downloadable).