Baby stomach measuring small

Hello all, worried mama here 33wks today, I go to a high rush ob and receive ultrasounds once weekly. They did a growth scan 3 weeks ago and said the my baby’s stomach was measuring in the 8th percentile.. and to increase my calories and they would re scan in 3 weeks.. well now after the scan they said it’s in the 2nd percentile and it worries me even more .. anyone go through this ? They seem concerned but i have no restrictions or instructions to so anything besides the norm.. baby is estimated to be 3lbs 6oz atm Tia