Confused about the mucus this month

Wendy

I had brown spotting mucus one day on the 14th of December and today 21st to now 23rd so far If I go poop hard same time very little little blood came out of my vagina with clear mucus. My period is due on December 31st. My last period was December 1st. I had sex on the 14 and 16 and 18th. I took my pregnancy test today and it’s negative still. Have anyone experienced what I’m going thru with mucus issues like that? I never had brown spotting one day during my mid cycle. Is that ovulation sign that day? Did I have sex at right time when that came?