I have a suggstion for how not to waste (not that you asked for that -- and I do sympathize with your problem. Been there a lot.)

Keep a notebook and make a plan for the day. Try out whatever you want. "I will write a short story." or "I will exercise and eat right (in some particular way)" or I will think about x and look for a solution. Anything. Then next day reread it, think about what happened, and evaluate your plan. Doesn't have to be single-day plans, but that's about the minimum length. Got this idea from some business website. I like it!