hi, i really dont know how to ask someone this, im a little embarrassed, ok, i had sex on valentines day 02/14/2009 and came on my period 02/19/2009, i had sex with someone else 02/28/2009 and 02/29/2009 and it was frequently we had sex, i found out i was pregnant 03/23/2009 because thats when i started feeling different, when i went to the doctor for my first ultrasound i thought i was almost 12 weeks judging from my period, the doctor looked at my baby and said my baby is about 13 weeks gestinational age and said i concieved on 02/23/2009 but i was on my period at that time and wasnt having sex, im really confused and dont know if the first guy could be the father or the second guy, because if i had sex with the first guy on the 14th, didnt have sex at all after him came on my period 02/19/2009 until 02/25/2009 and then had sex witha new partner on 02/28/2009 until i found out i was pregnant 03/23/2009 could the first guys sperm had survived from the day we had sex then though my regular period for almost a week and a half or could it be the second guys baby? please help