LADIES HELP!! I think I'm pregnant. I have every symptom possible. Only problem is I don't know when I conceived. I have no memory or record of my last period anywhere. I'm on birth control and I THINK I took 4 full weeks of birth control instead of 3 (switching packs) so a normal 28day cycle doesn't apply. I had sex on the 4/15. With my ex. And sex on 4/22 with my new bf. I don't know when I was ovulating because I don't remember when my period was. I THINK first day of last cycle was around march 21st ish. But the extended birth control messed my days up to count. Suggestions about finding my conception date?? If I go to Doc. Can they tell the exact difference between a 2week fetus vs 3week??