Help! negative OPKs

Samantha

I have been testing with OPKs this month. according to my app, I was suppose to ovulate within the past few days...i didn't and I thought maybe I will just ovulate later. There has always been faint lines on my OPK tests, but I took one this evening and there is nothing there besides the control line! Not even anything faint! What is going on?? Has anyone else had this happen to them? so dissapointing... the bottom strip is the one from today.