Large baby 😬

So 2 WKS ago, at exactly 29 weeks, our baby measured 5 weeks ahead.. 3lb 13 oz already just by ultrasound and body was measuring 34 WKS. I went today and Dr is calling for a growth ultrasound next week to measure baby again.. I am nervous of having a huge baby. She said that he had a lot of extra amniotic fluid as well 😬😬 anyone ever heard of this ? I'm kinda a small girl.. Weighed 130-135 before pregnancy and have gained 30 lbs so far at 31 weeks..