So confused! Help?

Hillary
So I was supposed to start my period a few days ago, but AF has not arrived. At this point I'm on cycle day 36 and that is super late. I took a test today though and got a BFN. I've had NO pms symptoms though like I always do. But I also haven't felt any pregnancy symptoms and I got the BFN today which makes me lose hope that I'm pregnant, but then my period is soooo late. Is it possible I'm pregnant and the urine test isn't right?!