I should know this as I've been ttc for 18 months! What do you count as CD1? If AF arrives in the middle of the day - and not spotting, a normal flow, would you count that as CD1? Online searches suggest it is the first full day so would CD1 actually be the day after?
I've stopped doing OPKs but have a rough idea of what CD I ovulate but I may be counting it wrong.
Thanks