Baby measuring smaller ?? Help🚨

Hello I’m wondering if anyone else experienced this. I had a 32 week growth scan today and my baby is measuring smaller than 32 weeks and since her head was so low they couldn’t get an accurate measurement of her head should I be worried ? Doctor said he would send me to see a specialist to get a better ultrasound he didn’t seem worried anyone else go through this ? I have gestational diabetes so he said typically babies are bigger not smaller.