worried I could be pregnant?

okay so basically it's kind of a long story. my boyfriend and I had sex about 2 weeks ago. we were first having it protected and then we had it unprotected. he's pretty good about pulling out. So he had pulled out and basically came on my butt and I think it might have slid down to my lady part. we wiped it off but I don't know if any of his cum got In. I'm supposed to start my period in a day. should I be worried? I'm super bloated and nauseous.