Period issues.. HELP!

I am a little confused right now as I have missed my period now for 5 days. My boyfriend and I haven’t had sex (were waiting for marriage), but he and I do get things going hot and heavy. Last time we did anything he came on my lower stomach but not even close to my vagina or any of that matter. I’m just a bit worried as to why I would be late?? I’ve never been this late before, and I’m not on any BC.