Probably just stress....

I use a few fertility apps. 2 said af would arrive yesterday. 2 others say today. Typically spot a few days prior. This month nothing!!! And no real sign of af. A little cramping but that's gone now. Ahhhh. I'm stressed at work wondering if that is messing with my system??? It has to be. Or is this our month? Trying not to get excited. Trying to prepare for the worst and to be happy if I'm wrong. How long do I wait to test???