Your body is in the process of recovery. The years of damage you've did with drinking now are beginning to heal. Your body is taking your energy and focusing it on repairing, thus why you're tired.
While still in early recovery you're discovering what it is like to deal with reality. Being sober at work is usually easy and effortless for most people, but as soon as the drinking time comes around, you're lost and confused and unsure of what to do.
Go for walks and drink plenty of water, walking is an unbelievable stress reliever.