Had protected sex the day my period was suppose to start and i am 6 days late now.

Me and my boyfriend had protected sex (condom) the day Glow projected my period was suppose to start. I didn't realize it at the time. I am 6 days late on my period now, I feel completely fine other than my breast being a little sore and having a small amount of mood swings. I have been under some stress lately with college, school, and a few others. I am a little worried though. Do you think I'm pregnant or could it just be stress and worrying about it? There was nothing wrong with the condom, him and I pay close attention to being protected. Any thoughts will help, thanks.