[Dream]

So I think my girlfriend might be borderline, but I don't know. In any case, how she acts sometimes is really damaging to our relationship and my psyche. I need advice on how to deal with this. I'll try to summarize what she does:

-Most of the time, she completely idealizes me. She thinks I'm the best, nicest person ever. Then sometimes she'll become very angry or upset, and she will criticize and insult me. There is never really any in between where she treats me normally.

-She is impulsive. She has ended friendships, left a job, and broken up with me on impulse (obviously we got back together). She also used to shop impulsively. She has spent over $1000 on purses and has a closet full of them (literally).

-I've never seen her self-harm or threaten suicide, but I know in the past she almost committed suicide before someone talked her out of it. She did say that she might as well die if we broke up, but I'm not sure how serious she was.

-She often has mood swings. Also, any little thing can set her off. Like, if someone is rude to her, she will rant about it for hours or even days.

-She sometimes becomes paranoid to the point where she loses touch with reality. She once went into a rage and accused me of wanting to cheat on her with her sister even though I had absolutely no intention or desire to and was not flirting with her sister at all.

-She is extremely clingy, and she will often guilt trip me to try to get me to pay more attention to her. I do spent a lot a time with her already.

-She is always paranoid about me leaving her, and she often takes things I do as a sign that I don't love her even though I do.

I don't know how to talk to her about any of this stuff since usually our conversations on these issues turn into fights. I do love her and would like to stay with her, but it seems like her insecure belief that I don't want to be with her or really love her is making it difficult for me to see a future together with her (ironically). I've tried reassuring her a thousand times, tried to show her, but it does no good I guess. Every few weeks or so, something will happen (or sometimes out of the blue) where she becomes very upset or angry with me. I've tried being as nice as I possibly can to her and have the best of intentions.