Anyone with elevated Afp? Spina bifida alarms?

I'm 20 weeks with di/di twins. I went in for my  anatomy scan yesterday because my Afp levels were slightly elevated. My scans went fine...ultrasound tech wasn't worried...genetic counselor seemed assured but Maternalfetal doc was not. Baby B refused to show her tail bone and I had to be rescanned. They got better views, but since her bottom was pressed against my uterus, the Dr. couldn't rule out a small Spina bifida. Now I have to wait two weeks to see if they can get a better view or have an amniocentesis or officially rule it out. I'm so concerned and my head is still spinning from everything. Anyone with similar experiences?? Any feedback is greatly appreciated.