I am 16weeks 3 days pregnant today (9/28/16) I had intercourse June 5th and June 21st . My LMP was forced by Plan B so it is inaccurate but the first day of my last period considering was May 25th, 2016. My doctors say my due date is March 12th. Which day could conception have been, the 5th or 21st? I usually have an irregular period and considering my LMO was inaccurate when could I have conceived? I took another Plan B pill an hour after intercourse on the 21st as well but never bled or had period symptoms.