I Sony know hoy many weeks i am

Allison
Hi question ? Anyone have had  a ultrasound on their First  week To The Obgyn. We found out we expecting not sure how  many weeks i am, i took The week test and it said 2-3+ líke a week ago. My app tells me 6 according  with my first day of period. But I am scary to go over and not see baby.  I had a miscarriage 5 months ago