About 15 years ago, I went through a period of time with my best friend like this, though I was the drunk caller. I wasn't drunk, I was just super angry at life, had just left my fiancee and didn't know what to do with my anger except project (and yes, drink but I wasn't drunk at this time oddly enough). My friend and her husband were friends of ours, and I guess I decided one night that they hadn't supported our relationship and this led to some of our problems (I don't remember exactly what fueled it; it was 15 years ago). Anyway, when I started getting angry, my friend just said, "Whatever!" and hung up the phone. I was angry for a few days, because that was kind of my baseline, but I got over it, emailed her, and we talked.

My point is that you aren't required to talk to someone who is being belligerent and abusive just because they are a long time friend. It is okay to set boundaries, and I think what you said was perfectly acceptable. You didn't start yelling at her or escalate the situation. You just cut it right off. Trying to reason with a drunk person is like herding cats.

I think that it's okay to give the situation some space, and maybe try emailing or calling in a little while. My best friend and I also went through a year of not speaking to one another, but I don't think that this is something which will come to that. Strong ties are not often severed by something like this.