For the ladies who use ovulation predictors

Sooo I'm new to upswing those pee on a stick daily ovulation predictors. I mean, I'm really new to using them, I just kind of pee on ten all the time in fact, like every time I go, almost as if I get a prize if I see two pink lines. Well for the past several days nodda, Iv been testing since Monday? That's kind of the day after I stopped my period, so I thought "well I have these things... Let's start peeing on them and charting." Well today I got a slight light line... Like really slight, then a couple hours later I tested again thinking it's going to be darker, and nothing! What's the deal? Did I miss my surge or something?