Back to square one?

What a lapse or a relapse mean to someone is a matter of perspective. Calling it "back to square one" would reduce to zero everything you have learned in your abstinence time and it might as well justify further use (if you've anyway "messed it all up" it's no point in carrying on).

Learning to deal sober with life challenges after (longer) times of use is a learning process. A (re)lapse might just show you which new personal skills you could work on.