The nagging need to be doing something may very well be some comobid anxiety. Isn't that fun?

What helps me relax is having time scheduled specifically for nothing, or "unproductive time," where I can let my mind can just function on autopilot. Maybe I'll decide to read, or play a game, or cook an elaborate meal, or go for a run. Whatever pops up, for as long as I feel like doing it. What's important is scheduling the downtime so that you can consider it its own task and you're less tempted to go be "productive." You can try it medicated or not, I've had success with the method both ways.