Pregnancy Scare

Hi guys, I'm 18 and my boyfriend and I had sex for the first time last week and we started out using a condom but then when I THOUGHT we were done he took it off and threw it in the trash . We cuddled for a bit but then I threw like a fake temper tantrum and he rolled me over and started playing with me then one thing led to another and he put it back in but with no condom . He came but I'm for sure he put it on my butt but I'm also 1 day late on my period . Should I be concerned ? Usually before my periods I'd have like pre-cramps but none of that is happening .