chances of being pregnant?

real, genuine question, how likely is it to get pregnant whilst on your period? i’m on it right now and am a horny little monster but I don’t take birth control and I want to have sex but if the condom broke and he finished in me what are the chances of being pregnant? i’m 17 and am a senior in high school and im going to go to college soon so being pregnant isn’t really an option for me. PLEASE LET ME KNOW!