Hi Claire.
I'm 40 and I use a CBM..I have used for for a few months now.My first month it was 1 high,2 peak ,then low...This happened around day 15/16.
This month I had the 1 high,2 peaks.1 high,then low..
Yours will probably go to peak tomorrow or the day after.Are you taking your temp as well?
Stick with it..
Hickson x