what does losing your mucus plug mean?

I'm almost 39 weeks FTM, and most definitely think I've been losing my mucus plug for the last few days. The first day it looked like a big booger, no blood (I had a cervical check, which I'm wondering if that caused me to lose it. 1cm dilated, 50% effaced, station - 2). Second day there was a little bit of mucus, with barely any blood. Today, we're back to the biggest underwear booger in the history of the world, no blood (picture below if you're a visual learner)... Any idea what this could mean? I know it could mean nothing and regenerate itself, but with 9 days until my due date...? Or is this just a whole new level of discharge?!