If your meds aren't working I suppose you could ask your GP to change it to something else. I'm not on meds but I know plenty of people who are and it was basically trial and error with their GPs until they found something that worked, after that it was only adjusting the dosage. But maybe I'm wrong so wait for more answers on this.

Now your roommate, well, she'll drag you down with her if you let her. I don't know if you're trying to help her because you care or because you fear that she's going to go berserk on you or something like that, but the fact is: you know that you have to take care of yourself first, and that alone is a difficult task to handle.