Last month, my period was 15 days late, so, with the chart that Glow had, I should be 9 dpo for this cycle, and on cycle day 30 but, I am very convinced I started my period, 11 days sooner than Glow predicted. Anyone else have this? Please someone has this happen to them too. I am driving myself crazy. Or is it just a case of IB? Not hopeful, (would like to be), but it is possible that a person who has always been regular with a 28 day cycle go to a 40 day cycle, back to a 30 day cycle?