My due date is february 5th 2015, when did i conceive?

Conception date: A due date of Feb 5th, 2015 indicates a last period of May 1, 2014. On average, ovulation would have occurred about May 15th. But as far as an actual date of conception this could be off by + or - 2 days quite easily. Also sperm can last in the cervical mucus for a number of days. All you can conclude from your due date is that you got pregnant from an act of intercourse anywhere from 5/8-5/17.