Baby measuring small

Just got results from my growth scan last Monday...My son is measuring small, 5th percentile. I now have to see a specialist an hour away from where I live to get better measurements and see what’s going on with him. Along with that I have to get nonstress tests done twice a week on top of my weekly doctors appts. I’m 34 weeks + 3 days FTM, and this has completely freaked me out. I knew he was measuring small, but I thought everything was fine. Has this happened to anyone else? If so, what happened?