Brown discharge at 36+1

Alison
Did anyone else get this before labor? Just started this evening, had a bit more discharge throughout the day (sorry TMI) and lots of lower back pain. Went to bathroom tonight and wiped and had brownish stuff on toilet paper. Not heavy just when I wipe and on panty liners. Have my weekly appt tomorrow with doctor anyway but wondering if this could be losing my plug or onset of labor?