Hi putnam,
This is a great place for venting
People here have been through it all, and we understand what you're feeling pretty well.
I wish there were some easy solution I could offer....but there really isn't one. Your mother's choice to go back to drinking isn't something you can control. You'll read that here often, in fact: you didn't cause it, you can't control it, you can't cure it.
I had the same problem as you are with detachment -- I wanted to be there for my sisters and brother when they were sober, but couldn't stand the pain of being with them when they were drunk. I too thought that "detachment" meant I wasn't there for them. That was a kind of black-and-white thinking that I discovered didn't have to be true for me.
It really takes some work, but I can tell you first hand what worked for me: I made it clear to all of them that if they contacted me while they'd been drinking, I would end the phone call (or not return the email or voicemail). I told them I loved them, told them how disturbing it was to see them killing themselves, and hoped they would choose sobriety. I was there to support them when they wanted to be sober, but I refused to engage with them when they didn't.
It was hard, but it was worth developing this skill, step by tiny step. Al-Anon helped a great deal, as did a little personal counseling. ALSO, the things you describe about yourself are common traits of adult children of alcoholics....the guilt...the obsession with helping....etc. I see you've also posted on the Adult Children board on this forum and that's great!! There's a lot of great support over there too, and be sure to read the Stickie posts at the top of both forums.
Educate yourself all you can. You will learn this isn't your fault, and you can't make it go away -- BUT you don't have to stop loving your mom.
Hugs,
GL