I have an important question that I have been trying to figure out for a loooooong time, basically since I became pregnant. Ok.. me and my boyfriend have been together for 3 1/2 years, but in the beginning of September of 2006 me and him broke up. At the end of september on September 29th and September 30th me and another guy had sex (well i guess you could call it that, it was unprotected, but we didn't finish at all, he put it in 3 times and then that was it, no orgasm or anything) Then the next week me and my boyfriend got back together and we resumed having intercourse.....I had a period on October 22nd and then another period November 21st thru the 28th (it was really heavy, so heavy that me and my boyfriend couldn't even have sex), then I had another period in December, but I am not sure of when I had that period, it was either dec. 18th, 19th, 20th, or 21st...Then in January my breast became very tender and I missed my period in January (all this time me and my boyfriend had been having unprotected sex and he came inside of me every single time)..January 24th I took a pregnancy test and it was positive. I got prenatal care right away.. my regular doctor asked me the date of my last period and I told her it was Dec. 21st, but i wasn't sure and she said that I was about 6 weeks along or so... So I got a new doctor for prenatal care and I continued my pregnancy..in May I had my 20 week ultrasound and when the tech asked me the date of my last period I told her that I really didn't know, but that I did have a period in Decemeber either the 18th thru the 21st..one of those was the first day of my last period, so the ultrasound tech at the hospital measured the baby and I was 20wks and 1 day pregnant and she put in that my last period was december 19th, then told me that the baby's measurements matched great with the date of my last period... My question is...when did I more than likely concieve?? AND could the other guy I had semi sex with be the father of my baby that I'm carrying?? PLEASE HELP ME !!!