Pleeeeeeease let me ovulate soon...

I'm starting to worry a little that I might not ovulate this cycle. Trust me...I know it's too soon to worry about this...I mean it's only CD 15 but I've been using digital OPKs since CD11 and I've gotten negatives everyday including yesterday. Last cycle I ovulated on CD16...I thought I'd at least get a positive OPK by now. I have 3 tests left in my kit and I'm wondering if I just wasted $40.