had sex with a girl last week - drunk/no condom/stupidity - anyway, we had sex for maybe 2-3 minutes (because of the lack of protection and she was on no birth control). I pulled out and finished myself off, which took about 10 minutes to do. I had urinated a couple of times before we had sex so I know there was no sperm in any (if any) pre-*** - but what do you think the chances are of her getting pregnant somehow or should I be ok?