Three days is great and I am glad you are feeling good. It is not unusual to experience an elevated mood at this stage. Enjoy it, make hay while the sun shines as they say. But be aware that recovery from alcoholism, if that is your problem, is never a linear affair.
At three days you are still detoxing. Alcohol is still present in your body and may be so for another three or four days. If you are an alcholic of my type, that can put you at risk of the phenomenon of craving, and of course, the obsession of the mind can return at any time, detox or months or even years later.
In case you were not aware, the phenomenon of craving occurs when alcohol is in your system, and manifest as an overpowering urge to drink more. The Obsession is just the idea that it is ok to drink because this time will be different.
The least I can suggest is that you be on your guard, but that alone may not be enough. Even better would be to put a plan in place for when you hit a bumpy patch, which is sure to happen. AA would be a good place to learn what is needed, but you may be like me. I resisted the AA idea to almost my last breath. Stupid of me, I know, but I had to be satisfied that there was no viable alternative.