Pregnant?

Me and my boyfriend always use a condom but I’m not on birth control. A bit ago we had a problem where the condom came off inside me but I took plan b in less than 24 hours. And I’ve had my period since then. In the past few weeks we’ve had sex but had no problems with it coming off I’m just not sure if some leaked out or something but for the past couple days I’ve been having the WORST stomach cramping and pain and I’m not sure if it’s IBS or if I’m just having a contraption problem but I’ve been googling my symptoms too much and now I’m freaking out that I might be pregnant. I’m 17 and really hoping it’s not that. I’m supposed to start my period in around 2 days but I’m really freaked out that I might be. Thoughts?