Big baby

My first baby was 9 lb 1 oz and I’m now 34 weeks and 1 day. I had a birth injury of femoral neuropathy with my first and couldn’t walk for a month so my OB wanted to do a growth scan to see how big this new one is going to be. Today baby measured 6 lb 11 oz and over 97 percentile head. The US tech said I’m measuring 37 weeks and 2 days which is 3 weeks ahead! Im kind of freaking out. I know I have my LMP correct and I don’t have GD. I am a smaller person as well. Not sure how he could be so big and I’m terrified my birth injury will be repeated. Has anyone been in a similar situation or have any advice or know what could be making my babies so big? I don’t see my OB until Monday. Thanks