H.J.
What is your new babies blood type is it also RH- if so you did not have to get the shot. It's only if the baby is RH+ that you need the shot, the two you got at 6 wks and 28wks were preventative just in case the baby was RH + I would check on that. Otherwise getting pregnant in the future either way shouldn't be a problem. Not getting the shot doesn't make getting pregnant any harder it just effects whether or not your body produces the bad antibodies.