Measuring small😔17th percentile??

Cl

Hey guys so I’m currently 34 weeks pregnant with my first baby and when I had my last ultrasound she said he was measuring a bit small and he’s in the 17th percentile. I have a high risk appointment on Tuesday to make sure everything is ok but I’m extremely nervous and worried that I’m not doing something right. I’m not a very big person myself (5’3, only gained 20 something pounds this whole pregnancy) but still😔

Anyone else go through this?? Any advice???