I follow poor old Ocean Princess around on these types of threads all the time.
I'm now 30 weeks and the baby's NT scan was horrible and ended up being an extremely horrible time for me. The measurement was 3.8mm and my BT test showed high risk for Down's. I got called in to the Dr and was told the chances of my baby having Down's was 1:2 and Trisomy 18 was 1:6. Just awful. They are extraordinarily bad odds. The chances of Down's was 50%!!! I was too late for a CVS and had to wait for an amnio (which we had decided to have). I waited 5 weeks for the amnio and had it on 18 Feb'. The results came back two weeks later completely clear. The baby did not have any of the conditions which literally had me crying for 5 weeks.
Now, the baby is still around and I've had the second scan - EVERYTHING fine. Everything has been really easy compared to what my
DH and I went through in the first/second trimester. This
pg has gone very quickly, but it is because I don't think I psychologically considered it started until week 21.
It's hard, but the stay off Google advice is very good. It's doom and gloom city there - just have you in tears. I was just a mess but remember you are not alone, there are quite a few of us who have been through this awful experience and most of us (as far as I know) have had a positive outcome.