TMI question re: cm on CD 1

Today is supposed to be AF's grand return.  Feels like she's real close and I'm real regular-- 30 day cycle.  I'm neurotically checking cm and it's white with some bits that stretch.  Took an hpt today and it was a BFN.  Question:  what is your cm like on the day (like, hours before) AF is due?  TIA for any and all help!!