I had sex with my best friend to came down from the navy on 02-20-2015, me and my boyfriend got into an argument so at the time we weren't together. He went in without a condom for like 15 seconds not even close to a minute, then he put on a condom. So on March 13th or 15th me and my ex when back together, so from that day on we had unprotected sex multiple times. This June I found out I was pregnant, but my periods are irregular so I don't remember when I got my last period. We guessed and just said March 1st and that would put my due date as 12-6-2015. When I had my ultrasound the day after they said that the due date was still the same and this was at planned parenthood. So then I went to get an ultrasound somewhere else and they told me I was 2 days ahead from what PPH told me so my due date was 12-4-2015. So my concern is that my ultrasound may be wrong and it's my bestfriends. Please give me your input and help me out.