3rd day placebo? No period?

So I'm on my 3rd day of the placebo week and still no period. My boobs have been hurting for a week and I have had some cramps which is normal for me as far as pms symptoms. I had sex for the first time a few weeks ago. And have been having sex regularly after. I take my pills exactly the same time everyday and haven't missed any, plus we use condoms and I'm positive none of them broke because I checked them with water after. So what's going on? Where's my period?