This hasn't happened to me in a very long time. But my plan would be to pick up the phone and call someone immediately. And I don't just think about it, I react by doing it. Because if you think about it, you'll think yourself right out of doing it.
Like one of the previous commenters said, play the scene forward. You might feel a little relief in the very beginning but it is very short-lived. When you wake up you will feel much regret knowing that you accomplish nothing and now you have to start all over again.
It's called believing the LIE; that this time, everything will be okay. But it never is, is it?
And let me put this bug in your ear. Relapse doesn't start when you pick up a drink. It starts long before that. So if you even think about picking up a drink, something is missing in your program.
If you're not going to meetings and don't have a sponsor yet I would get one and start going. And make sure you get a sponsor that is willing to take you through the steps because that is the psychic change you're going to need if you're going to remain sober. Just like it talks about in the doctor's opinion.