The angry outbursts to me sound like the effects of the alcohol, rather than anything else. Indeed, BPD is a lot more of a reasonable diagnoses for the angry outbursts than Bipolar Disorder but if she's consuming alcohol, that right there could explain not only the angry outbursts but also the depression that she's experiencing.
Of course if she was in a similar way before consuming alcohol, then there may be something else to blame. However I don't believe any qualified and experienced psychiatrist would diagnose a mental illness or personality disorder when there is alcohol in the equation.
Some psychiatric medications can also cause agitation and irritability, but psychiatric medications are obviously not a factor in this case.
Hang in there. It sounds really trying! I cannot stand it when people not only self diagnose but then use an illness they're not even diagnosed with to explain their unreasonable behaviour. Mental illnesses can often cause people to react in ways they wouldn't normally find acceptable behaviours otherwise, and in that case I can understand people using their disorder to explain their actions as it could indeed be to blame. Using a disorder you're not diagnosed with as an excuse is however, in my opinion, a very bad thing to do.
RB.
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Bipolar life has it's ups and downs
Currently experiencing slight relapse into depressive episode but overall stability for almost a year!