I have very regular periods, my last period was on June 9th and My Bf and I had sex on the 21st we weren't using any protection, he noticed that he finished and quickly pulled out and had semen all over his hand, he didn't fully finish inside me. About 2 hours later we buy opcicon one step which is the generic brand of plan b. I was on antibiotics for about 4 days I was taking Bactrim and ciproflaxin. After I took the morning after pill, I got headaches for about 5 days. Sore breast lasting about 10 days. Two weeks after the incident, 5 days before my period I had CM with stringy blood! There wasn't any clots or heavy bleeding. I started thinking that I really was pregnant! Thinking it was implantation bleeding. It didn't stain my underwear or anything. I thought that I had gotten my period, I was excited and I thought yay it came early. I was even cramping which is normal because I always do right before I get my period. 5 days before my period I took a first response pregnancy test and it read negative. I took another pregancy test the day before my period was due and negative again. I'm sure now that I'm not pregnant. I know that I will most likely get my period late because of the pill. But wow this past weeks have been nothing but stressful! Constant wondering if you are pregnant or not! Googling every little thing that you notice about your body! These 2 weeks were just awful and just doubting every little thing! Don't do it!! Always be safe! Everyone's body is different but this is what I experienced hope it helps someone ! My advice is talk to your gynecologist