Pregnancy and babies weight

Destinee

I’m really nervous, I’m 31 weeks pregnant and only 12 months pre-op but my doctor is now concerned about my baby boys weight. He is only 2 lbs and should be about 4. So I now have to do weekly ultrasounds. This is my first baby, and have been TTC for 7 years. I didn’t think it was possible due to endometriosis and PCOS I know they say after surgery it jump starts your fertility, and boy is that so. Where your babies on the smaller side? Did anyone conceive to soon?