Draw with a goal and a purpose. Hells bells - even write down what you are trying to accomplish. "I need an environment of type X". Then list out what should go in it, colors, etc. Check off each step from thumb nail to larger picture. When your objectives are complete (notice I said objectives and not your actual product) then be done with it. Maybe give yourself a timeline.
Main question_ how do you stay motivated and enjoy the work when you feel like you can't even. :'(
The commentary is just a gift to you.