am I? I feel weird?

So me and my boyfriend had sex on Easter and the condom broke~ we immediately went out and got plan b and I took it within those few hours and have had sex with a condom on and he always pulls out (wearing a condom still) before he comes~ i Just got my period but it was light and lasted three days when it's usually heavy and last three to four days~ I just started having sex and I don't get birth control till next month~ I have high anxiety so maybe that's why I'm worrying so bad but could my light period mean I'm pregnant or is it cause of the plan b and just starting to have sex? Please help~