I have had these recently, and they're so vivid. There's a bar I used to frequent near the city centre which is licensed to serve alcohol at 8 am, and I still dream that I'm anxiously waiting outside for it to open...it's horrible. I'm so relieved when I wake up.
As others have said, I think it's a normal part of recovery. The fact that it's a nightmare, i.e. it's an unpleasant dream, is a good thing and as it appears that my subconscious is registering alcohol is a bad thing. At last!