It also depends on how long your period is. The average cycle is 28 days (though this is different for everyone and also depends on your age). Day 1 is the first day of your menstruation. Day 14 is ovulation day. Sperm can stay alive for quite some time - 7 days, I believe? So you can see, if you have a 9 day period, your chance of getting pregnant from sex 2 days after your period is quite a lot higher than if your period would be 3 days. But it is never zero. You can still get a morning after pill; you can use it until 72 hours after the contact (though it works best if you take it as soon as possible).
I will run 45 minutes by the end of April! Up to 15 17 20 23