Congrats on day 4! This early on it can be really tough.
For my first sober week I planned out the weekend before hand - set out to paint a room, redecorate my studio, e.t.c... anything to keep my mind far away from the possibility of drinking.
Like Fandy said, try something you haven't done since forever - something that booze kept you from tackling. When you complete a task like this it gives your sober mind a nudge that there's a whole heap of reasons you should remain that way and not get pi$$ed anymore.
It helps, believe me.