I'm having twin girls. Two sacs, one placenta. What is that Di/Di?? I get confused. 

So last week I had an amnio done. The quad screening came back high risk for Downs and the NIPT test came back low which I thought was good and the NIPT test was a better test. Despite that, my doc encouraged an amnio because of the inaccuracies with twins. I swore I wouldn't do it but I did. Still no results. What also alarmed my doc was that one of my girls has a 2 cord blood vessel and not the normal 3. Meaning, she may not get all the nutrients that the other baby is getting . She's already measuring 2 ounces smaller. Today my doc said that can change so that was good to hear but I'm feeling all kinds of worry. To boot he put me on meds to prevent contractions- Procardian?- and it's making me feel light headed. 

I just feel drained and overwhelmed. I normally vent to my mom but she has no idea what any of this means because even though she's had all 7 of us, she never had twins. 

Has anyone had any experience with any of this??