Confused - cbfm and OPK saying different things

Hi Atomic - hope you are well.

I have started using the cbfm which worked well for me when TTC last time.

It said peak yesterday and 2nd day of peak today however the OPKs are negative.

Do you know what might be going on? This is CD 13 and I am having around 30 day cycles

Which would you trust more? The cbfm or the OPK?

Thanks, Victoria

Either one of them can be wrong. I would have an attempt now and keep testing. if you get a positive on the other OPK in 4 or more days, have another attempt. Otherwise stick with this one.