Well, it isn't impossible to get pregnant if the ejaculation was outside of the entrance to your vagina, although it's very unlikely. But, you did take the day after pill so you are probably not pregnant. Don't worry about it. Also, that pill works different for different women. I have taken it twice in the past 4 years on separate occasions and each time, it made my period come. I have also read on here that it did nothing to some other women and their period came on normally, while others were delayed quite a bit. So my best suggestion would be, if it doesn't come by your expected date, don't panic. Since this happened about 9-10 days ago it'd be too early to take a test anyway so you'll just have to wait it out. Good luck!