It's such a stressful time, I know exactly how you are feeling. Is there any chance you could have your NT scan a bit earlier? With my last pregnancy I booked it in for 13 weeks, and bub was measuring 13 weeks and 4 days, and it was a lot harder for the sonographer to get the measurements she needed as the baby tends to move around alot more apparently when you pass 13 weeks. Just a thought. I'm sure everything will be just perfect