So my ultrasound this morning went well. Dr. V saw one sac measuring 4.8 mm in diameter. What a relief!! He also saw another sac that is very small and Dr. V said he doesn't expect that one to make it. We go back in two weeks for another ultrasound. I can't help but hope we hear two heartbeats at that next appointment, no matter how unlikely it seems.
Here's a picture of the larger sac.