How am I not pregnant?

Okay so I'm 17. I dont want to get pregnant and ik I'm literally so stupid for this, but I'm really confused as to how I'm not pregnant. My boyfriend and I have never used protection and he cums in me every time. We have sex quite often so like??? Could I be infertile??? I have a genetic disorder that may make me infertile but like idk

*I know I'm not pregnant considering I am on my period right now *