I had my followup ultrasound today to see what's going on with Mary.
The two iffy sacs from last time are indeed nonviable. They have yolk sacs, but neither progressed beyond that point. I'm extremely conflicted about what's happened. I wanted a singleton pregnancy. For many reasons I'd hoped not to have multiples and I am relieved to have one, healthy baby, at this time. However, knowing that the other two eggs did fertilize, that I should have two more babies is hard. I am mourning their loss and wonder what happened. I'm very glad and grateful for Mary and hope he/she continues to thrive and do well. I am also comforted by the fact that the other two sacs contained yolk sacs, but no fetal poles or babies.
As for my "Mary" she is doing wonderful. Mary measures 7w2d and has a strong heartbeat of 153. My due date is April 10th. My next appointment is September 6th.