it's so painful for the family to witness the throes of alcohol and the self destruction of loved one. i'm glad you offered to go with her to a meeting. and ACOA's do need to distance themselves somewhat. it's protecting one's self. have you considered attending a meeting of ACOA? you need the support of others and will find ppl who are/have gone thru what u're going thru. ACOA can help you find a healthy way for yourself of dealing with a family member in active addiction. alcoholism is a 'family disease' as you readily know firsthand.
the other thought i have is why not pick the right time and tell your mom how her drinkingg makes you feel. try to pick a time before she's gotten too much booze in her. maybe that will create the spark for her to consider how her alcoholism affects you and the sadness you feel.