Period is a no show. Need advice

Kyra
My periods are weird.. and Glow says I was supposed to get it the 18th but I haven't and it still hasn't come yet and I still have cm.. Do you continue to have cm until your period comes or does it become dry before your period? Or if you don't get your period because you're pregnant does cm continue to show or does it become dry? Usually my periods are 24 days apart sometimes 28 or 30 but it hasn't been like that in a while so I'm just really confused bc I'm trying to conceive just don't want to get my hopes up and be let down again.