I Have Had Prolonged Diarrhea For The Past Month But

I have had prolonged diarrhea for the past month but in the last five days it has turned bright green and is pure fluid. Anti-diarrhea pills don't slow it. I have also had more headaches and migraines than normal and fainted twice three days ago with a massive body temp. I am on meds but none are new and I have been on them nearly a year. What could it be?