It's very, very, very unlikely, almost impossible, that you would be pregnant from that. Although them spermies are good swimmers, the trip is much easier for them when there's actually penetration. If I were you, I wouldn't worry about it at all.
If your period is late, it could simply be because you've been worried about this or maybe even some other reason... There are about a billion reasons why your period would be late.
But if you're worried, it never hurts to take a pregnancy test to give yourself peace of mind about it. Like I said, though, I really don't think you're pregnant.
Since all of the answers are pretty much going to repeat, I'm gonna' go ahead and close this. If anyone thinks it should be reopened
PM me and I'll see what I can do.