Had a scary ultrasound

Has this happened to anyone before? I went for my first ultrasound today, HR was 173, measuring at around 8 weeks, but my OB said during the ultrasound she noticed that the “nuchal fold” seemed a little bit big, which she said she recommends me getting an additional screening done around 11 or so weeks, doing another ultrasound so they could measure it to see if it might indicate a chromosomal abnormality like Down syndrome. I’m now officially freaked out and I have to wait 3 weeks to test. She was very nonchalant about it and just said she thinks I should have additionally screening done to get it checked out. I’m worrying now and will be for the next 3 weeks that something is wrong with my baby. Has this happened to anyone else and it turned out ok?