Levonorgestrel
"I had unprotected sex several times and I wasn't on BC, although my partner did pull out in time. I wasn't educated and I didn't think you could get pregnant through precum. Anyway, I took levonorgestrel two days in a row (Mexican off-brands), within eight hours of having sex both days. I didn't notice any side effects the first day I took it, but the second time I felt very nauseous and had a headache. For the next two weeks, I experienced nausea, moodiness, headaches and other uncomfortable symptoms. After a week, I had withdrawal bleeding. I waited a couple weeks before taking pregnancy tests and they all came back negative. My period was almost 4 weeks late. When it came, it was the worst. But I'm not pregnant"