2) Let go of any other guilt or pressure to do something more valuable with your time or improve something that you already know how to do.
3) Accomplish a small goal that is unrelated to your larger goal. The more unrelated, the better. If your goal is to start a company, teach yourself calligraphy instead or learn how to prune a fruit tree.
4) Once you're feeling good again, you know, where you feel good doing stuff after your normal work, take a look at your original goal. Can you start working on it again? Has the break given you a fresh perspective on it? Can you break it down into small achievable chunks now?
5) If yes, do that. If no, go back to 1.