So sorry to hear about your results josie57, I know it sounds ridiculous to say don't worry but it might all be nothing.
I've been looking up all the evidence on nuchal measurements, given our mega 4.8mm score, and even high measurements still only bump up the likelihood of problems by a small amount.
They just classify everything over a certain amount as high risk because by doing further tests on all those over that amount, they know that the odds are they'll pick up 90% of babies with problems. BUT - this is the important bit - they will also test an awful lot of babies who have no problems whatsoever!
Wishing you all the best for those blood test results, hang in there