I had a csection and about 2 weeks pp I got that then was completely done bleeding and having that discharge by week 3. so in my experience it seemed to mean I was ending my bleeding time it may be the same for you
not sure how you delivered. but with my second c-section (5 months ago) I bled for that long or longer and it was dark brown as well...and quite a bit of it too. didn't have any discharge like that though