late period

Trisha
Hey! 
So I'm late on my period and I'm worried that I might be pregnant. I'm not usually 4 days late, this is the most so far that I've been late for my period. 
I was wondering, should I be worried yet or wait a couple more days until I should be worried? 
I've been stressing a lot because of this but I know stress delays your period but I can't help but stress because we've had sex so much this past month. We've always used a condom. 
Any ideas of suggestion?