Hi herehare, I am almost the same as you so handholding if it helps.
Just had my 12wk scan this morning and our baby was the same - very fidgety and the sonographer struggled to get pictures, then called me back in to rescan - not internal, but still a worry as we could see the readings she was taking and had (perhaps unfortunately) already read up on what they might mean. Readings were coming up as 3.4 - 4.0, and the final 'official' reading was 3.8mm, which they said was borderline risky (apparently 3.5mm is the 'border') so I've been referred. I was taken straight from bloods to another clinic to speak to a midwife, who gave us some info and called the fetal consultant. We've both read loads already about the various potential problems (finding out as much as poss is how we personally deal with things best) and the consultant I spoke to was great. We decided to go for a CVS as we need to know asap rather than waiting and worrying, so I called the consultant back as soon as we got home and have been booked in for the CVS this Friday. We were told that the NT result means the bloods will be rushed through, so we should hopefully have that result early next week, and the consultant thought that some of the CVS results should also be available next week. It helps me to know that we should have at least some information, good or bad, within a few days, so maybe you could ask if they can give you a timescale, if that would help?
I can't offer any reassurance as such but if you want someone in the same boat to talk to, PM me. We've not told anyone other than our parents (due to a MMC earlier in the year) so not able (or really wanting) to talk it through with friends in real life.
The consultant I spoke to focused very much on the positive stats rather than the negative, and a lot of what we've read seems to do the same, which helps a little bit with the worry, but DH and I just want to get as definitive answers as possible asap so we can make whatever decisions might be necessary. Fingers crossed that the outcome is good for both you and us.