You could just start the new package and take the whole thing. There will be no problem if you skip the period week altogether. It would dangerous (you might get pregnant)if you didn't take the whole month's worth of active pills, though. More is better than less. You can always take more than a month's worth of active pills, but you can't take less than 21. You might have some spotting if you skip your period week, but that's normal and doesn't mean it's not effective.