It's actually what's know as an orphan chemical. It's related chemical, THC, and source are both illegal, but CBD is not (in the US at least...), allowing it to be sold as a supplement. This may be changing soon, so if it's something you're interested in trying, I'd do it soon, so you can stock up .
Edit- I have a similar cycle of extreme swings. My heart goes out to you, and I hope you're able to find better ways to cope and to continue producing wonderful art.
RE: Back to black