I am currently pregnant and due on june 18th 2010. i hd sex with the same person i have been having sex with for 3 years on the 16th of sept. i then had a one night stand on the 20th of sept. with another man. i am trying ot figure out when i concieved my child, and who is likely to be the possible father. my periods are not really normal, my last perios was aug. 9th and i didnt get it in september at all. help?