Do you think I'm pregnant?

Ok so my boyfriend and I were grinding and it just slipped in. He pulled out before he came but I'm really stressed. I've been having really irregular periods like the last two have been 34 and 39 days. I'm on day 37 right now and I'm incredibly worried. It's been 18 days since that happened and I've had some weird digestion problems and the last few days my breasts have been slightly sore. Those are the only things I've noticed. I know it was stupid that it happened but it really wasn't supposed to and now I'm incredibly stressed out that I'm pregnant.