Thank you all so much for your kind messages of support. I can't tell you how much it helps right now.
I am so sorry Bookmiser about your terrible loss. Thank you for sharing with me about that. Maybe it is a small comfort to know that what you said, has helped me greatly! I am indeed a newbie - I only realised my mom was alcoholic in January. Actually I confronted my parents the same month, and they haven't stopped arguing about it with me since, trying to prove there is no alcohol or drug problem, and saying my behaviour is disgraceful etc etc. It is amazing watching their denial at work, now that the scales have fallen off my own eyes.
Anyway Bookmiser it feels like you are saying there is the guilt my parents are currently foisting on to me; and then there is the bigger picture. You've reminded me the bigger picture is more important.
Thank you Bluebelle too. Your experience sounds a lot like mine. Why do we feel guilty for setting boundaries...? I guess because they are breaking 'family rules' and because they make the alcoholic feel some sort of pain?? When I look back at the boundaries i set (I wrote them down so there would be no confusion) they seem entirely reasonable to me! (e.g. if my mom gets mashed at her house, I will leave the room; when they visit me, they have to stay in an hotel .....)
Thanks again for everything you have all said. I am feeling so much better today for it.