Could I become pregnant?

So I started my period Sunday through friday morning. Meaning I should've been on a new birth control pack as of today on day 4. I have yet to start the new pack and had unprotected sex Friday. I would've been on the first 2 days of a new pack. Anybody got pregnant like this? Could I even get pregnant like this? What are the chances in all reality. It's too late for PLAN B?