I'm still in the first few weeks of my recovery but I've been having them as well. The worst one was actually just last night. I've been fasting for the past couple days as well and I had gone to bed soo happy that I've managed to stay sober this long, and with the fast I'm feeling 100% mentally and physically, never fealt so good that I could recall. Went to bed, I dreamed that I had drank, and I woke up within my dream telling myself it must have been just a dream, and got up and went to my desk to find empty beer cans everywhere, horrified it wasnt a dream I went back to bed all upset/depressed (all within this dream). Woke up after that and it actually took a few minutes for me being awake and confirming no empty beer cans for me to actually believe it was really just a dream.
As much as I hate these nightmares they do act as a reminder of where I was and could be. And the relief realizing it's just a dream makes me appreicate waking up sober even more.