emergency contraception
"I realized I had been with my partner on a very fertile day, about 14 days before my period was due.  I panicked and took Plan B about 20-24 hours later.  I was able to buy it at Rite Aid over the counter, which was a relief!  I took the pill and had no side effects until about the time my period was due, and then I got a migraine aura twice in a day.  Very scary, but I am prone to migraine auras when my hormones change.  I figured my period was very close, but it didn't come.  I had no other symptoms except maybe slight nausea.   Finally, 6 days later I started spotting and having cramps.  Hallelujah!  I've never been happier to get my period.  It was 6 days late. So don't worry - this medication DOES work."