Never used OPKs with my first. We for pretty lucky and conceived after 2 months of trying. Now we are 4 cycles in and nothing. My period has been so weird and it is messing this app up with my highest chance dates. I’m going to start using OPK strips to make sure I know when I’m ovulating. Can anyone tell me exactly how they work? I’ve seen women on here say they pee of them several times a day? And the second line has to be as dark as the first or darker? I’m a little confused lol