Hi, I'm Using The Clearblue Fertility Monitor And Have Been

Hi,

I'm using the clearblue fertility monitor and have been for quite some time.
It's always been pretty regular an lh surge around day 11 and peak on day 13-15.
This month lh surge started on day 10, I'm now on day 17 - lh surge still high and no peak.
Cycles vary between 28-30 days.
Slightly confused as to what's going on. Any ideas would be appreciated.

Thanks so much

Michelle