Welcome and congrats on your pregnancy! I am due on 1/15/14. I had a loss last December at 10 weeks, so I totally understand the anxiety. I felt a lot better once I got past that point in the pregnancy, and the anxiety decreased a lot. Has your doctor recommended a cerclage or other treatments to prevent premature membrane rupture?
As for hair, mine has been super curly lately, though that could be due to the humidity here. It's normally 2B/3A but has been looking more consistently 3A with maybe some 3B-ish pieces. Maybe that's what's happening with you--the curl has increased so it looks like there's no growth due to shrinkage.
I also have barely been shedding at all. The same thing happened when my two older children were born, then I lost a ton of hair between 3-6 months postpartum.
Best wishes for a healthy pregnancy!