Nervous for no reason

I just got off BC last month, and just got this app in the beginning of Oct. But, per Glow,my fertile window took place on my vacation,so there was lots ofBDing. Now it says my period should be tomorrow, and no sign of that happening. I'm tempted to test, but know that I will be ridiculously stupidly disappointed with a BFN. So I'm thinking of waiting for a few days after Glow says AF is due to test. I'm just posting here bc didn't realize how scared id be to get a negative so early in the process....