Period days late!

I just recently started using eve and before I did my cycles were pretty routine:every 28 days. Since using eve my cycle is a little longer, but this month my period is 5days later than the normal 28 day cycle and 3 days late from the one eve projected. It's finals and my bf and I had been fighting a lot in the past month, I was wondering if this sounds like it would be due to stress or if I'm possibly pregnant?