What day of cycle did you start using OPKs?

Women O on various days in the cycle for me I was lucky to find it was always day 13 (I was charting). A common mistake is some women text using OPKs in the morning like you would a pg test when in fact it should be a lil later in day (say early afternoon) I was one of those women

lol
Cramps in the middle of the cycle could possibily be ovulation too ...
Good luck x