There is nothing more annoying that feeling like that, I know it well.
To fix it I spend my every available moment loading myself with more and more work. Example, I've gotten a New Year's Holiday. This means I'll have free time, which means I'll feel down.
How to fix it?
Get rid of said free time. I've done this by taking on 20 different tasks for Fuwanovel. Make threads in the staff forums. PM dozens of people. Brainstorm, brainstorm, brainstorm.
With this, I'm both productive somewhere, and I also enjoy my games/VN's/Anime more, because I feel like I'm resting.