BBT drop post O for 2 days below cover line

First month charting.  I have some difficulty knowing my CF well and distinguishing it.  I feel like it changes throughout the day from sticky to wet, etc.  also, I had a dip then a rise for a day, then a dip below the cover line for 2 days in a row.  I have an average of a 28 day cycle  and stick pretty close to that.  No opk checks, but is it possible to get a few days of dips post-O and still have ovulated. I should also state that I am a very restless sleeper.  Any thoughts?  I find this all very fascinating and dot want to get discouraged.