I use both the cheap opk strips & the Clearblue Advanced. For 3 days on Clearblue I got flashing smiley (high) then ran out of tests so bought a new box of Clearblue. Today should've been my peak day & test strip confirmed that however I got a "low" fertility on the new Clearblue ??? Is this bc it's new & doesn't know my cycle yet? So confused. Any help greatly appreciated.