Baby's stomach measuring small

Courtney
Just went for my 32w ultrasound - baby is measuring small. I go back on Thur to have an AFI/NST. Dr said "don't freak out", get some rest, and he just wants to make sure baby is getting enough nutrition and has enough fluid. Then he'll measure my belly in 3w for the most accurate reading for my size. Any mamas experience this? Baby's stomach measurement fell within the range it should, but on the lower % (9.6%) so that's why he's bringing me back in so soon. Of course it broke my heart because our first babe was born at 9lb and I had a super healthy pregnancy, aside from running low on fluid at 40w. Anyone experience this with their diet baby, or experiencing it now?