Help.

Mariel • I don't need an inspirational quote, I just need coffee

Ok so my period is a day late (not much but I get worried) I had protected sex during my least fertile day and my partner wasn't even close to finishing when he pulled out. I'm showing all my PMS symptoms for 2 weeks but my period hasn't appeared. I know sex can change your cycle and I have been stressed lately due to my classes. Could it be that?