Clearblue Advanced Digital Ovulation "low" to "peak"

My husband and I have been ttc since our missed miscarriage in Feb and my cycles have been all over the place since May  and I haven't been sure when I ovulate so I started testing with the first response fertility line tests (CD 15)  but kept getting negative readings so I decided to try out the Clearblue Advanced Digital Ovulation tests 4 days ago (CD 25) and all of my tests have come back "low" (blank circle)  fertility then today (CD 29) I got a "Peak" (sold smile face) fertility! (Yay) I never got the "High" (flashing smile face) fertility reading between the "low" & "Peak" Has that happened to anyone else? 
P.s Also If so how accurate were they for you and were you able to conceive that cycle?