should i get plan b

so i was having sex with my boyfriend and after i noticed i felt weird down there. we used a condom so i checked it and there was like a tiny tiny rip in it. when i checked it, it busted. i’m 2 days away from my period and i’m unsure if any even got in me. i know it’s unlikely to get pregnant this close to your period. should i spent $50 on plan b, or would you say i’m safe? lots of people using the calendar method for family planning (or the opposite) would have sex 2 days away from their period and be fine. i’m unsure of what to do, and i really don’t have $50 to waste at the moment.