I took ECP during my fertile days which I use an app to calculate and its been very accurate for the last 3 years. I had unprotected sex with hubby and took next choice 35 hours after. I started cramping and spotting brown (no red) 6 days later, I figured I would have started my period already but it has not. I'm cramping more as the days pass. Today I have cramps but no spotting at all.