emergency contraception
"For those are you who are scared or anxious about the Plan B pill, I just wanted to reassure you from personal experience that it WORKS, and isn't necessarily full of side effects either. I took Plan B and the only side effect I felt was a little bit of moodiness for a couple of days- otherwise, NO physical side effects at all. Also, my period came exactly on time and didn't feel any different than my past periods! 

However, I would advise that you definitely should take it within 24 hours, if you can. Although it says 72 hours, the pill mainly works to prevent ovulation- if you wait too long to take it, you may risk ovulating BEFORE you take it, lessening the main effectiveness of the pill."