B.B.
Congratulations! I cannot offer advice on the ultrasound but agree that you should stay positive and try not to worry. Focus on the miracle of twins! I just love having twins. It is an amazing experience from the very beginning and it is not twice the work. Just get them on the same schedule from the start for feeding, sleeping, changing, etc. Makes life easier on you and them.
My biggest twin advice is to try to find a local Twin Mom club to join while you are pregnant. The other mothers are such a great resource for information and support. Plus, it is a great way to buy / sell tons of baby gear! Just Google it or you can check this national website for leads in your area http://www.nomotc.org/. Also, loved the book Ready or Not Here We Come!: The Real Experts' Guide to the First Year With Twins by Elizabeth Lyons.
Best of luck!
B.
Mom of Twins
www.babybearsden.com