Family member's alcohol problem affecting my mental health

Apologies if this is not an appropriate subject for this site---if it isn't,if anyone can recommend a source of help for me(I'm in the UK),I'd be very grateful.
I have a serious anxiety/depression problem,and have had lots of support from this site in the past. I'm just emerging from a very bad phase,but now have another stress.My sister has had mental health issues since adolescence,and I have usually been the one to offer her support.We both suffered an abusive childhood,but she is especially damaged.Has had a series of relationships which have been both physically and mentally abusive,
She has always used alcohol(and sometimes drugs),as a means of coping,and has had spells in psychiatric hospitals,but she has difficulty in seeing herself as worthy of help,and tends instead to take on a caring role with her fellow patients,refusing to discuss her own past.
The irony of all this is that I am a qualified psychiatric nurse,and also a social worker---I actually specialised in addiction,so I know a bit about my sister's problems from both sides of the fence,as a helper,but also a patient.I just seem to have held it together a bit better,and I've had the support of a wonderful husband,and a good Dr. Things have deteriorated recently----we have always been so close,but last week she rang me,very drunk,talking of how we didn't deserve the abuse we suffered,and accusing me of not keeping in touch with her(I write regularly,and send surprise presents often).This has affected me very badly---my husband has always loved and supported me through my periods of illness,but I fear for him,as I now seem to be spiralling downwards from anxiety to serious depression again.
There are help groups for the relatives of alcoholics,and I spoke to someone involved in this,but my current anxiety levels are so high that I couldn't attend a group at present.I feel a need to withdraw from my sister(on the phone,at any rate)but this makes me feel so sad and guilty.
Apologies for the length of this post,also if it isn't appropriate.How can I maintain my mental health in the face of what is a terrible tragedy?
Thank you for listening.

Thank you so much for your kind words.I will be taking a look at the book you recommended.It's a weird situation;I must have counselled and helped thousands of people through detox,and I've tried to help my sister from every angle,but you're right---alcohol changes people,and it's that which destroys me.
My sister is a kind ,gentle,person who empathises strongly with the abused and down-trodden.She is a fantastic musician,and has made her living from this,but tragically the alcohol has affected her voice,and I fear that won't come back.
She has an 11 year old son,and seems to use him as a confidante(she is separated from his father,so doesn't see her son as much as she should).I literally weep at the damage she is doing my nephew,who is a very quiet,intelligent child,who has already seen more than a kid his age should.My sister has become very selfish---I hardly know her anymore.
Anyway,thanks for giving me a chance to vent some of these feelings.
All good wishes to you.

Dear Kitt,
Thanks for what you say---I too fear for my nephew,and it's a measure of how my sister has changed;I would never have believed that she would behave in front of him as she has.
For myself---I seem to be losing it on a grand scale.I rang my Dr,and she is going to call me sometime today,to discuss how to handle the situation,re sedation etc.I also contacted an organisation here,who provide counselling and support for relatives of alcoholics,but whether my anxiety will permit me to keep the appointment,is anybody's guess.Better take this one day at a time.
Your offer of prayer is gratefully accepted,and I will reciprocate.

dysthymia
I am glad to hear you have upped your dose of Valium. If you need it right now and it is working for you I think that is a good thing. I still use mine when needed as it beats sitting around crying all day or afraid to go out the front door of my house ( my safe place).

It is truly amazing your sister has no major damage to any organs and your right to not try to talk with her right now re how you are feeling as it may cause your house of cards to come crashing down.

I am glad you are enlisting the help of your siblings as this is a burden nobody should have to deal with alone if others are available to help.

Please do make sure you take care of you first. Know when it is time to take a step back and just make sure your OK. Your mental health is most important as I have found out. smhair I do understand how we want to be all things to everyone and when we cannot it makes us feel inadequate but I learned the hard way that I cannot save the world............but I can save myself.

I admire your devotion to your family and how lucky they all are to have you. Your one awesome person !
I hope your day is a good one.

Gentle Hugs
Kitt

May I suggest Al-anon? If you're not familiar with it, it is a group for family members of alcoholics and the goal is to help you learn how to live your life rather than having your alcoholic family member direct it for you. The philosophy is not negative about the alcoholic, merely affirming to the family members.

I have had several friends who found this program to be very helpful in dealing with this situation. My step-mother used it in her first marriage, and when she and my father married she would use some of the techniques on my dad even though he didn't drink at all. She was amazingly effective in not entering into his rants.