I know for me personally relapse started long before I took the first drink or drug. It started with thinking like you are having now. Once I made up my mind "nothing could stop me", or at least so I thought. In truth, I could stop me, if I made the choice to.
You are doing well to reach out for help here. That is a good first step, one I often avoided, and still do in truth. Now you have to take what you are learning and turn it into positive action. Play out your drinking to the end. What is it really going to be like. Use your past memories and be honest with youself. Remember how you finally quit 12 days ago. Do you really want to go through that whole process again?
The final decision rests with you. You do have a choice. You can combat those thoughts creeping into your head trying to take you back. SMART
SMART RecoveryŽ Help with Alcohol, Drug, and Other Addictions has some worksheets to help you sort out these thoughts.
I can think of a couple of members, ZenCat and Alera, who have both stayed sober using these methods. AA may also help if you haven't tried that. The choice is your's, you can plan to relapse, or plan not to. Best of luck.