I'm sorry I can't really help. You just have to stick it out for a few more months as you said (it will be here b4 you know it) and part of it may be the stress of being broke. The money problems are probably really affecting her mood. See if you can get a hold of some extra cash somehow or something. But, your description of her mood swings sounds like some of my friends who are & most likely are Bi Polar (no offense to them, your mother, etc.) If she has something serious like that causing her anxiety & depression (if I got that right) she REALLY needs her meds & you need stress relief. Cheap stress reliever compared to pills include dark chocolate (calms me down & it lowers blood pressure) & their are herbal supplements (like St. Johns Wort & Melatonin/which I take/took). I am NOT a docor, so I would not take my medical advice if I were you w/o consulting a doctor or doing your own research (just threw it out randomly sorry). Just relax, if you are leaving after you graduate, more to look forward to when you graduate! Whatever you think, her problems are not your fault & you do not need to take care of them.
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Balance is needed within the universe, can be demonstrated in most/all concepts/things. Black/White, Good/Evil, etc.
All dependent upon your own perspective in your own form of existence, so trust your own gut and live the way YOU want/need to.