What could brown vaginal discharge mean? In the past two weeks I have been diagnosed with diverticulitis (though they can't be sure) and given birth control for pain management from fibrosis sis. Today and yesterday I started having brown vaginal dischar

Please see a doctor. Much if medicine is ruling out the worst thing first. Or at leat making sure you don't need urgent treatment. With diverticulitis i would worry the brown discharge was stool or blood from a fistula. A fistula is a connection between things that should not be connected. Hopefully it is just abnormal menses. Good luck.
Brown . Brown vaginal discharge is concerning for a vaginal infection. You should be tested for pregnancy if there is any possibility, and should have test for infection. If you have increased pain, fever, vomiting, or light-headedness, then you should be seen as an emergency.