OPK confusion and ovulation on diff cds

Kayla
I use clear blue advanced digital opks. The first time I used them in September I got peak on cd 14 this time in January I keep getting a flashing smiley (5days) and I'm on cd 19. I'm trying to understand why I haven't gotten a peak yet and would i ovulate that far apart or should you ovulate around the same cd each month!