My OPKs are driving me nuts. My periods range from 28-34 days. I started tracking day 11. The first day Clearblue was low fertility symbol, then has advanced and the last three days I've had the high fertility flashing smiley. Progress, right? Problem is I have three other brands of OPKs, from the cheapest kind, to Walgreens brand, to first response. Sometimes the lines are darker in the morning, sometimes darker at night. Tonight they were nearly nonexistent, all the while the Clearblue brand is flashing that smiley face at me.