Twin Question

I went for an ultrasound this morning as a follow up to some bleeding and not seeing what they should with my hcg level. I asked if there was a heartbeat and the tech said it's complicated and then explained she sees what they saw at the ER two weeks ago and then she sees a baby with a heartbeat... I'm shocked first of all that there are two but I don't know what's going on with the other one. I have an apt today to talk to my doctor but I was wondering has this happened to anyone else and what was the outcome.