First, let me say good job for being sure to use condoms. I would say your boyfriend is probably right that there wasn't a problem with the condom during sex and it happened after intercourse. Broken condoms are very noticeable and generally, they don't leak at the bottom until a penis goes flaccid. So, I sincerely doubt you risked pregnancy here. Irregular periods make it hard to know. But you'd get a positive pregnancy test in around 2 weeks if you did conceive. But I would say 99 percent you did not get pregnant. good luck