Missed period on Yaz

Hey girlies,

I'm on the last (placebo) pill of my second month of Yaz (not to be confused with Yasmin). I'm on the 4th sugar pill and I still have NOT gotten my period. I know that with most other BC you just wait and it will eventually come - but with Yaz the sugar pills are only for 4 days. Do I start taking the next pack even though my period hasn't come yet? Do I grab a pregnancy test?

And if it makes any difference, I skipped my period for the first month I was on it. I know I should have let it come to get my body used to it, but I was on vacation at the beach :p Also, this is the first time I've ever taken birth control.

Thank you for any help :)