Of course all seems meaningless without mental stimulation. Try to walk to stimulate your brain. Your at a place where it might take very little effort to get you back into the swing of tjings. Just find a place a do a long walk(45 min) or jog. Drink a large cup of coffee first and see if that'll get you back on track. Exercise is #1. You can just pace back and forth in your room to get that stimulation back. Don't throw in the towel. Its just biochemistry. You might be amazed. Prime that pump. Get that mower going. Drive that ATP. Cellular respiration. Victory!
I was pacing all winter long in my room like a weirdo. never was I so productive. Count 1 for each end of the room. Its a goal. Count to 100 or 200.