Ohh your sister's comment makes me think... if you're telling people you're an alcoholic, then yes, people are definitely going to try to tell you that you're not. I think it's just because they don't understand that alcoholics aren't all loud, pissing themselves and breaking bottles all over the place. They think you're being harsh on yourself.
I was a secret drinker so I had this problem. The first time I quit I told my family I was an alcoholic, and they had almost nothing to say about it. Later when I'd relapsed I even drank in front of them and they just thought I'd figured out I wasn't really an alcoholic. They're not big drinkers, so I know it wasn't because they just wanted me to drink with them. It wasn't until I had a total withdrawal melt down in front of them with liquor bottles stashed everywhere in their guest room that they finally understood what I meant (now THIS looks like tv!).