Help!!! 39 weeks, tmi (sorry), but freaking out!?

ok, so i am 39 weeks and i am scheduled for a section on wednesday. i have been a little crampy tonight and i have been having contractions for weeks, but nothing like active labor (baby is breech, so i am not dialating or effacing). i just went to the restroom and had the strangest (i'm sorry for the details) discharge, and a lot of it. it doesn't smell, it is dark brown/black/green, and there is a lot of it...has this ever happened to anyone? what is this??? should i call the doctor or just see what happens? i never read anything about this, it doesn't seem like a bloody show or a mucous plug....it's really weird!! any help would be appreciated - thank you!