Would love some advice please. Sorry for the long post but this is my first visit to this forum. I'll try to get right down to it

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I have a mother who has a personality disorder. I am not sure exactly which one, but she has traits of BPD and traits of narcicisstic. I am at a loss about how to handle her anymore. I'm at my wits end. Mine causes me such pain, grief, embarassement and stress - it's absolutely horrible sometimes. The older she gets, the worse it's getting. I just can't bring myself to "walk away" or cut myself off to her, as she is a wonderful grandmother to my son. I feel bad for he too - she's driven everyone else in her life away pretty much and I'm all she has and I know she's mentally ill and really in some way cannot help it - but I can't seem to find a way to deal with her crap. I'm so tired of all the crap she puts out.
Our most recent issue centered around Christmas of course - as it does every year. We all have to walk on eggshells when it comes to Christmas. An example of this behavior is she thinks the world revolves around her and everything should be dropped when she says to. The latest is she got mad at my sister because she had plans with her husband's family last night for christmas. Well my mom wanted to have a sleepover with my nephews and expected my sister to cancel her christmas plans with her husband's family so that she could see the kids. It's totally ridiculous. She guilts the heck out of everyone for everything. My brother and my sister have for the most part abandoned her and they really won't put up with her antics anymore. I feel like I am all she has, but she drives me fricken insane. She has no insight into her illness either. She thinks the problems in her life have nothing to do with her it's always everyone elses fault. She can't hold a job for more than a year or so at a time. She's worked for every engineering company in town now. She was fired from her last job due to personality issues and lots of other jobs she's quit just before they were about to fire her. I wish I lived in another province

. But she's 10 minutes away from me dammit. I am the only family member down here near her.
There is some sort of huge drama issue with her at least weekly. If it isn't her job its her parents, or my sister, or my brother, or her neighbors, or she's dated yet another guy she doesn't like, or she's told yet another friend to get lost.
I go to great ends of the earth to make sure I have done everything I can to make her happy. She is suicidal sometimes, and I worry if I (the last person in her life that truly gives a darn about her) cut myself off from her, she'd kill herself and I would never be able to live with myself if that happened. I would feel guilt about that for the rest of my life and I'd probably end up in the psych ward myself. To top it all off, I myself struggle with severe anxiety and depression. Ugh.
I guess I'm just looking for some suggestions on how to deal with her. I've seen counselors who basically have told me I need to cut her out of my life. I've read a book about boundaries. I guess what I'm looking for is some advice on how to handle her without cutting her out of my life because I just don't feel in my heart that's the best thing for either of us. I do love her. She's my mom. She gave me a wonderful childhood and it's not really her fault she's mentally ill.