Levonorgestrel
"It works, I had unprotected sex three days before I started my period. I took the pill about 28 hrs after I had unprotected sex and for the first few days I was panicking, waiting for my period to start since I was supposed to start it. And sure enough I got it, I've never been so happy to get my period. The pill didn't affect me at all, I ate before I took it and went to sleep so I wouldn't notice the effectiveness. If you're stressing out like I was, all I can say is keep calm and wait."