Study-break rant!!

I don't deal well with people who are emotionally high maintenance; i.e., I can't stand when a person is your friend, literally calling you her best friend at the time, and then suddenly starts accusing you of things you know you didn't do, then after a few weeks acts as if nothing happened then goes right back to acting as if you are the plague a few weeks later. As far as I can tell, I did nothing to provoke these changes in either direction. I know I have started reacting to this latest change with obvious anger at times. I occasionally let a sarcastic, smart-ass comment slip out, when I can't manage to censor myself. For the most part, I try to stay out of her way and out of conversations with her so I don't say anything I may regret later.

The problem is she lives with a person I tend to spend a lot of time with therefor I spend time at her place on a regular basis. I always feel like I did something wrong I am not supposed to be there when she is around. Her roommate says any mention of me results in a snide remark of some sort and it is often implied that my presence is not welcome at her home. Lately these comments have revolved around my studying in their living room and taking advantage of her roommate's offers to pay for my dinner when we go out to eat.

I practically seethe with anger when I start thinking about her. I do try hard not to, not for her sake, but for her roommate's because I don't want to get between them. Funny thing is, she hasn't said a thing to me about any of this. I haven't brought it up with her either because I think it will just make her more angry with me and I don't want to do that, though I am starting to not care if I do. I know she is emotionally unstable at times, but this has progressed much farther than I thought it would. I don't know how to deal with this situation anymore. I haven't been over at their place more than 2 or 3 times during the last 2 weeks, but her anger towards me hasn't decreased, if anything, I think it may have gotten worse. I am at a complet loss on what to do next, if I should do anything at all.