I'm confused about my conception date. My doctor says I'm due march 31 I did the online due date calculator online and it says I conceived July 8 this is when I had sex with my ex July 7. Though my LMP was June 16 and when I put it In on the online due date calculator it says I would be due March 23 and Imy conception date would be June 30 and I've been having sex with my boyfrIend before and after I had my last period I'm just confused please help.