NST every 3 days????

im 30 weeks. I just had an ultrasound today where she watched baby breathe and watched his heart. she also checked the heartbeat to the umblical cord. She said today everything looked good and that my results were being sent over to the hospital to be looked over. she said i would be there once a week for monitering. amd to check flow through the chord.

the reasons for this ultrasound is bc he is a small baby, his legs measured small at 25 weeks, stomach measured small at 28 weeks and he only weighed 1.13 lbs at 28 weeks. I have an appointment with a Dr that specializes with small babies. but now i also have these NST every 3 days instead of once a week????

does this mean the women at the hospital saw something the tech didnt??? im so scared. does anyone know what possibly could be wrong???