Abnormal result in first trimester scan - Advice and help needed


I’m 12 weeks and 6 days today and had my first trimester scan. The results showed that there was too much fluid in the back of baby’s neck. I was told 3mm and under is normal but my baby’s was at 4mm. They took my blood to do a test to get a more clear answer of genetic disorder. My husband and I are devastated and very worried but hopeful that the blood test comes back negative. We were also told that even if the blood test comes back negative, they will need to do more testing for other issues as to why there’s abnormal amount of fluid. Has there been anyone else that has a similar experience but everything turned out ok?