Anatomy scan 20 weeks- small head

Hi all

So we have just had our 20 week scan, everything was going really well until the end when she mentioned the head measurements were slightly on the lower end. Husband reckons he saw the measurement as 162.5. So now I need another scan and to see the fetal medicine consultant.

I’m now worrying myself silly that it’s something I’ve done wrong and baby with have microcephaly.

Has anyone experienced this?! Or give me some advice please. Stressed out mummy and daddy xx