I hadn't lost any weight on the scale from November through December (was fighting the same 3 pounds) and then once I started working out with the trainer...doing more balance, more heartrate and more cardio...then I had a whoosh.

I think with you it might be opposite in that you're starting with the weight training and your body does need to adjust. (I was doing some heavy weights on my own in the fall.)

But if you keep building that muscle and working that body, it'll come off!