How long should I wait before testing?

Me and my bf had sex on Saturday, and I just stated my placebo pills yesterday as well. Last month my period was light, and this month it has yet to come. I had some cramping about 3-4 days ago, and have been feeling like my period is coming, but no period yet. It's only been about 2 days, so I'm not that worried yet. Just wondering when I should test, I know that it sounds kind of silly to worry. But he did pre-*** a little before the condom went on. I was playing with him, he didn't go inside of me at that point. I just want to make sure I am not pregnant :P