The Condom Broke.

So on July 26th, my boyfriend and I had sex. We had a condom on, and for once we decided to have him finish inside of me.. well after we finished it discovered the condom broke, it had a petty big hole, we're pretty sure it slipped entirely through the condom... I do take Birth control but I just started my pills back on Sunday after my period week... I took Plan B about 6.5 hours after. I'm so scared, has anyone had this happen before?