Pregnant?

Me and my boyfriend just had unprotected sex (literally 30 minutes ago) and he said that he pulled out a bit late. I saw that he had less cum than he normally would. But he said that he's 99% sure he didn't cum inside of me. But if he did, and he only came inside of my opening of my vagina, would i still have a high chance of pregnancy? Since he didn't cum all the way inside of me? I just T finished my fertile window and I'm on day 1. (14 days till I get my period). What do you guys think? Pregnant or not? I want to buy plan b but I can't get my hands on it till 1-2 days. And I also don't want it to mess up my period. But I'll get it just to sure.