I think you;re beating yourself up a little too much here. That kind of self hatred can lead to more drinking.
You had 16 days - and you don't lose anything you learned in those 16 days.
you know how to get sober - now you need to work on staying sober...it's not back to square one...you have a running start
look at your recovery programme and think of things you can add now, pudsyh
D