Advice on dating measurements

Courtney
I'm currently 36weeks 5 days and just left an appt where my doc measured the babies head at 33 weeks and 3 days. All of my dating scans have been pretty consistent and accurate up until today. I have a formal scan in about an hour with a better machine. Has this ever happened to anyone and things turn out ok? This will be my first baby after 5 previous (early misscariages). I'm sitting on egg shells, worried sick!