worried

At my last ultrasound at 28+4 baby was measuring 2 weeks behind but at my 20 week anatomy scan she was measuring perfect. Has this even happened to anybody? I’m a second time mom and this didn’t happen with my son. They scheduled another ultrasound when I’m 31+4 to check her growth and if she’s still measuring small I’ll have growth scans for the rest of my pregnancy. Im just worried that something could be wrong with her 🥺🥺