hi Teech
Cant offer much concrete advice really. I have yet to master the OPKs! Are you using Clear Blue sticks? the ones with the smile when your surge is due? In my experience, you never get a smile when you think you probably should. The advice seems to be, test more than once a day so you dont miss the surge but the Clear Blue sticks are so expensive, that seems an expensive way of finding out your fertile window. I have some cheapy sticks I bought online. Other people haves suggested to use those until you get a 'dark line' and then use a CB to see that smile! Good luck!