I am so sorry you lost your little ones. How heartbreaking.
I agree with the other girls about your uterus going back to size and giving yourself time to heal emotionally and physically. I had a m/c on September 28th and then got pregnant again on my 3rd cycle (in December) and now am going through another m/c (but I dont think it has anything to do with the amount of time I waited). I'll probably wait a full cycle and start trying again on cycle 2. Guess I would call the doc too if you wanted an exact reason why. HUGS