Baby Growth

I had my growth scan today at 32w4d. I have GDM and although all of my numbers have been fantastic with only diet control, I’ve been worried about both overgrowth and restricted growth as apparently both can happen. Baby’s head was measuring 32w1d, his length was 31w5d, and his weight was estimated at 4lbs even. They told me overall he is 16th percentile, which is down 3 percentile from a month ago. My doctor is not concerned, he said even 6 days behind is not outside of average. But I am worried. Anyone else have measurements/sizes for their babies and what they were told is to be expected?