I'm a nervous wreck

I had my anatomy scan today. I am 21 weeks and 2 days with our son. And they found bilateral choroid plexus cysts in his brain. They said that everything else looked perfectly normal and that they should resolve on their own but I am scared shitless..I also had the maternity 21 genetic test done earlier in the pregnancy and he tested negative for all trisomy disorders including trisomy 18. Has anyone gone through something similar? Looking for some ease of mind. I have a 2nd ultrasound done in 4 weeks..I'm so worried for my baby.