Levonorgestrel
"I was with a guy for a pretty long time and this one time the condom broke and he had came  inside...  slowly he pulled out and that's when we knew that it broke. Well at that given moment, I freaked out and then a lot things were going through my mind. But my partner was there to calm me down. We then rushed to our local CVS and purchased the Plan B Formula. I took it an hour later after the incident. After 3 or 5 days I started experiencing some kind of brown/reddish color coming out my vag which was one of the symptoms I experienced. I also experienced headaches,nausea & minor cramps. But nothing I couldn't take. At the end I got my period a day later from usual."