I had sex on January 12.It was while me and my boyfriend were split up. It was unprotected, but he pulled out. Then I got back with my boyfriend and him and I had sex on January 21, unprotected and he did not pull out. I am pregnant and had two ultrasounds, one at 6 weeks and 1 day and one at 18 weeks. Both said I am due on October 16, meaning the date of conception was January 23. How accurate is this and how probable is it that the baby is for my boyfriend?