Here's a picture of when my last period was. How should I work out when I conceived my baby? I'm confused because a doctor would say from the first day of my period which would make me roughly 7 weeks, I have 40 day cycles so my last period was due the 22nd August which means I'm only 5 days late. This app says im 4 weeks 6 days, but I took a clear blue digital and it says im 1-2 weeks. I read that you can get pregnant whist on ur period, I had sex the 16th August and couple weeks after that (sorry for tmi) I would just like to know is it possible I conceived on my period or is clear blue digital most likely to be right?