I felt the exact same way you did earlier on and it still visits once in awhile. That feeling of slogging through mud where you don't want to do anything. I think mainly, it's our body saying it needs a break. Alcohol creates so much chaos, we just need a rest from all the changes when you stop.
When I was drinking I would try to do everything 200%...after all, an alcoholic couldn't hold down a demanding job, or be a good caretaker, or get everything done right? If I did everything I was supposed to, so what if I liked drinking? When you stop, all that extra pressure you put on yourself goes away. It almost created the opposite in me lol "now that I don't drink I don't have to be so damn responsible all the time"
Hang in there, after awhile you'll notice more energy starting to creep back. Lots of water! Lots of naps and showers. Anything to shake you out of the stupor...