Is Pregnancy Possible Despite Being On Birth Control Pills?

Hi, I ve been on birth control for two years. I had sex with my boyfriend a few days ago, the last day of my active pills for this pack. I never was late this entire pack, or ever really. But the condom broke and we didn t realize til after. He pulled out, but he came as he did so. I think some got inside me...I m so worried. I didn t get plan b because I know it can mess with birth control and I know that birth control is reliable. I m just scared.