thank you both, we went back to the dr today, and what he thought was another amniotic sac was some blood... i have a hemotoma of some kind, something like a bruised uterus
IT couldve been another baby, but that your already 13 wks without that second heartbeat, its likely your only having one.
It IS possible that another baby was hidden. It could be that there was another twin, but it didn't continue to develop, explaining why the HB wasn't detected...it could also explain your bleeding.