I guess how you handle this is a choice. I mean, if you think this person is truly trying to sabotage your effects? Then heck ya, see ya friend. And really, what's the big deal? You are sober, you know you want to be, her issues are hers.
Could also be that she's alone and missing her drinking buddy. If she's a true friend, maybe suggest coffee with her? Maybe then you can really explain to her that you are not, ever, going to drink with her again. If she can't respect that, tell her you cannot remain friends.
I am frequently faced with situations that have the potential to irritate me, anger me, frustrate etc etc. The key to keeping my calm is in how I choose to react.