According to Glow my period was suppose to start 7/14. When it didn't show up and I "deleted period" from the calendar it just changed it from 7/14 to 7/21. This in turn changed my fertile window from two weeks ago. Why is it changing my period days instead of acknowledging that it may be late? This has discouraged me as I was excited to be late for AF but now it's switched everything and I didn't BD during the new fertile window 😔