I have a feeling that even if you didn't live together, she would only contact you to discuss her problems. She displays a high degree of self absorption when she discards your issues so casually.

Does she ask you for advice at all? Or, does she just want to be heard? Friendships must be mutually beneficial, or they will not survive. Anger, bitterness, loathing and resentment will kill it. You're her friend, not her agony aunt. Remind her of that.

If she doesn't get that , then you should stop being so available for her.