E.B.
I know it's hard, but try not to worry. And stay off the internet! I didn't have this, but a similar situation where they saw something unusual on an early sonogram that could have been x, y and z....and I had to wait for a month before I had another one! Of course I went online and read all the most terrible cases it could be. It turned out to be just fine, nothing at all and I now have a happy, healthy 8 month old daughter. Try not to worry, keep positive thoughts and remember that the odds are extremely high that everything is perfectly fine!
Good luck!