Hi fist day of my last period was November 15 I did not get my period in December, today I had an ultra sound and I was told I am 6 weeks and 3 days pregnant I was told baby due date is September 29 2014 when did I get pregnant ? on what day ? I had sex November 30, December 1,2,3,10,11,14,15,16,17,19,20,24, January 30,8,9,10,11, is it possible that the ultra sound estimate is wrong? that am 6 weeks 3 days pregnant? could it be more or less?