Smelling things that aren't there response

So I posted the other day about smelling things that aren't there now that I'm pregnant. Recently I started smelling baby spit up I thought I was going crazy then I posted on here and other woman are expirencing the same things. So I posted on health Tap and a doctor responded basically saying its our mind naturally making us smell these things since this is my second pregnancy I know the smell of spit up & that's why I keep smelling if.. Here's the doctors response