Could I be pregnant?

My cycle is always irregular. I've had 34 and 36 day cycles before. It's usually a little more or less than 31 days, and today is day 31 for me. I've never had vaginal sex, but me and my boyfriend fool around sometimes (oral sex, dry humping, etc.) My boyfriend and I were dry humping and he had underwear and jeans on, while I just had my underwear on. He didn't ejaculate, but I'm afraid pre-cum could've gone through my underwear. It was on my last fertile day. If anyone could give me some feedback, that would be great. It's been worrying me for almost a week. :/