Usually I get a positive OPK anywhere from day 17-23 and it's cd 25 today and no positive OPK :( I've had some cramps close to ovulation but no positive OPK or change in cm (it's became watery but still creamy) this happens every 2-3 months and of course it would be the month that I was booked in for my 21 day progesterone test and got pre seed! Aghh. What is the cause of random cycles with no ovulation?