Microcephaly?! Anyone experience this...?

I'm WORRIED SICK! My baby boy has been on the smaller side for the entirety of my pregnancy. At my 28 week scan, they found his head was around the 3rd percentile...

I had a consultation with my doctor & he said that it would technically be considered "microcephaly," but he sees these numbers "all the time" & most babies are completely fine upon birth.

I'm just wondering if any of you moms had babies measuring quite small, even below or around the 3rd percentile, that turned out okay? No microcephaly? No impairments?