If you can do it swimming is an excellent form of exercise as the water supports your body.

I only had one piece of maternity wear to pass on to the charity shop, I was lucky enough not to have to go out and buy a lopad of clothes for a few months. I've got a friend who is battling with her weight ater pregnancy and an under active thyroid, she eats well and healthily but just can't seem to shift the weight. I'll direct her to this thread so she can get some support and ideas too.