Babies head measuring 2.5 weeks behind

Jewel
So I had my 36 week appointment today and the babies head is measuring behind by 2.5 weeks and in the 2nd percentile. The Dr didn't seem worried as everything else was above average and this is the first ultrasound where her head circumference has measured smaller. I see a high risk doctor on Monday. I'm still nervous and worried. Anyone else have this issue?