Broken condom

While having sex the condom broke and we didn't notice until the whole thing was over. I took a plan b but I'm trying to decide if that will be enough. I am 19, my boyfriend and I have been together for almost a year but are not prepared for an accident like this. I am not on any other form of birth control and am supposed to get my period today. My period has been consistently coming late for the last like 5 months.