It's impossible not to stress, but TRY!!! I've also been on the receiving end of bad results - the test is only accurate to a point. If you want to know for sure you will have to go to CVS or amnio. I was given an NT meausrement of 2.3mm (which is only the upper end of normal), but with bad bloods, my ratio was 1:10 for
ds, and my bub sadly was the one. I've read of so many with higher measurements whose bubs are fine, so just try to hang in there and try and assume the best.
Lee