I am panicking!! Baby measuring small! I need opinions!

So I went to the dr yesterday, right before I got seen they told me i was due for some blood work, to check for DS, and abnormalities. So then an hr goes by and I’m finally seen by the dr and he’s checking everything.. her heart beat is strong and he measured her length, legs, stomach and every was perfect she is measuring exactly 18 weeks and 5 days, which is how far I am. Now he measured her head and I swear I saw it measuring at 13 wks and 5 days, I automatically knew that’s not right or something is wrong. I was in shock but dr didn’t say anything he said baby is weighing 9 oz rn and she’s big and everything. So we left the dr and my dumbass goes straight to google and I see microcephaly and I started panicking having a full blown anxiety attack and I spoke to my Fiancé about it and he started panicking and we both started crying because everybody wants there babies healthy. And then he told me to text my dr so I told and I told him what was going on why is the baby’s head measuring 1 month behind and he said the baby is healthy and nothing is wrong that maybe I saw the wrong measurements but I know I didn’t. So now I’m just panicking and been crying all day. I don’t know what to do or think..