Babies measuring small

Any mamas have babies that measured small? Had my anatomy ultrasound at 20 weeks but they weren't able to get all the measurements so I had another today (25 weeks tomorrow) and they said baby boys measurements are all normal besides one being his tummy is slightly small. They said he's 1 pound 6 ounces and in the 9th percentile so I have to go every week now and see the high risk Dr for the next 4 weeks. NIPT genetic tests were all normal and they say not to worry but it's hard not to. 😔