Well, your period will probably come when it should. You need to be using a back up method of birth contorl until you're a week into taking another pack with no mistakes.

You can start the new pack whenever you'd like, just know that if you start mid cycle then it may take mess a bit with our cycle and you're more likely to have breakthrough bleeding for awhile. I would wait until my next period and just use condoms until I'm protected again, but I don't have a lot of patience with things like breakthrough bleeding-- its up to you.