Problem Ultrasound

I went in for my 20 week ultrasound and baby was measuring small. They marked me as IUGR or growth retardation. Baby is only at the 8th percentile in size, but is proportionate. They are sending me to get a stage 2 ultrasound for further investigation, took my blood for chromosomal abnormalities and said I will probably need an amniocentesis at this next ultrasound. Looking at my online chart for blood test results I saw a confirmed choroid plexus cyst from the ultrasound as well. They never mentioned this to me. Has anyone ever dealt with this? I'm 26 years old pregnant with my first baby and freaking out. If you've gone through any of this, what were the results?

Thanks.