I had an ultrasound on June & the doctor said my due date was on October 18, 2012. Then I had another ultrasound on September and the doctor said my due date is October 10, 2012, but if I count 38 weeks back from those due dates that would mean my baby was conceived before my period. Could I have been pregnant during my period?? The first day of my last period was January 17, 2012 & I know it was definitely my period because it was the whole 7 days.