I'm a little late!?

Aspen
Hey so I'm 17 years old, and I'm a couple days late. Me and my boyfriend had protected sex a couple of weeks ago and he didn't come. Buuut Idk I'm still worried about Pre-cum probs and rips. I would like other people's opinions and advice. 
Alright, this is only freaking me out because I have never been late before, if anything early. And we always make sure the condom is in probably and that there aren't any rips after the fact, but we didn't get to this last time. What could possibly be causing my period to be late?