Well, the big day finally arrived. I went in for the scan, and saw ONE sac, and ONE little embryo. I couldn't see the heartbeat, but the doctor said that she could see it. It was still too faint to measure the heart rate, but the doctor seemed to think that all was well. Whew!
I'm about 1% disappointed that it's not twins, but 99% relieved. While in theory, twins would be wonderful, given our situation (thousands of kilometers away from family and friends, living in a foreign country on a single salary), twins would be really hard. One is perfect.