I'm pregnant and my doctor said my due date is Sept 22, 2009. I had sex on the night of Dec. 31, Jan 1, 2 so on. The reason why I'm confused is on the due date calculator it said that I would of most likely conceived between Dec 25-30. Which I didn't have sex because I went home for the holidays. Prior to that I had sex Mid Nov, but not for the whole month of Dec till I went back to my BF. I know I had a period somewhere between 12/20-12/25. And the only reason why I got that due date is because my early u/s estimated it, because I didn't know the actual first day of my last period. Can someone please help me understand this.