Measuring Small

Ma

At my last doctor appointment my doctor said I was about 2cm too small so she scheduled an ultrasound at the perinatal diagnostic center in the hospital for tomorrow (Wednesday) to make sure everything is okay. I've gained over 25lbs, but I was very thin and tall to begin with. Baby is very active still, and he's moved into the head-down position. Has anyone been told they were measuring small and everything ended up being okay? Currently 37.3 weeks and so worried for my baby!