We've all had mishaps in our recoveries, and for many different reasons. One of my problems was seeing my decision to quit through more than a day or two. Finally I realized that the decision to quit is not a recovery plan. It's just a decision and an easy one to talk myself out of. Recovery is a change of lifestyle, change of mindset, and a process of implementing a way to see that decision to quit into long-term sobriety.
In other words, you need a plan.