Clearblue Digital Advanced OPK help

I just started using the clearblue digital advanced opk yesterday as I have a 29 day cycle and the test said to start on cycle day 9. I got a low fertility result yesterday and expected one today as well as I didn't think I'd ovulate until around September 8th. The stick showed high fertility instead. Anyone else have a high reading only the 2nd or 3rd day of testing? Did it stay high for a while or did you peak sooner than expected?