Hi,
I am 2 -4 days late on a 21 to 23 day cycle ( never longer than 23, in the past 3/4 months), meaning I'm on day 25. I was expecting my period yesterday after some horrible cramps, and instead, I only got yellowish discharge. I've had weird back pain since (probably not related). The ovulation predictor didn't detect anything when I took it this morning... And I know it can predict the same hormones that increase during pregnancy.