Having a problem with a co-worker at my job, how should i deal? Kinda long.. any info appreciated.?

this is hard, mostly because this woman really doesn't want to get better, she is using her depression and sadness to manipulate everyone and everything around her. I am surprised her boss hasn't done something about it yet. When I was that depressed, my boss told me keeping my job had become dependent on getting counseling and medications, so I went. It was the best favor my boss ever did me.