This is my first cycle OPK testing. I started testing on CD10 in the mornings - always getting a very faint line. On CD14 AM I got a darker line but still not dark enough so started testing in the PM as well. My PM tests are not dark enough . Both control line and test line are faint. The lines seem like they are getting darker in the mornings but not sure why you can hardly see them in the PM. I am on CD16 and this is how my tests looked today and this is how they’ve been looking for the past couple of days. Darker in the AM and lighter in the PM. I’m nervous I’ll miss my surge. Anyone have any advise?