I hear you, brother.
I am currently going back on Wellbutrin after six months off. It's making me a bit manic at the moment. I went off because I didn't want to have to take drugs. I was feeling better and thought I could do without (ha!).
A couple things to keep in mind. 1. When you start a drug, herbal or pharmaceutical, you body will go through an adjustment period. The crazymeds guy some great things to say about this http://www.crazymeds.org/SideEffects.htm. I especially like the paragraph that begins, "These are powerful, alien substances..." While he's referring to prescription drugs, this may apply to SJW. Given that your body and mind need time to adjust, you may need choose a better time to start taking SJW. Sometimes it takes longer than a few days. Maybe getting better will require a good week where you can afford to just be deliriously happy. Or just be. Does your work have an annual slow period or can you create one by working ahead for a while?
2. Maybe next time, start with a lower dose and work your way up to the recommended amount. Maybe half is all you need to get the affect you want.
3. You sound ambivalent about happiness. That might warrant some further reflection. Did it feel good? Maybe too good? Why shouldn't you feel really good? Growing up, did you get the message that good stuff must be experienced in small, stingy amounts? If not, what other beliefs do you hold about good things? That they are limited, rare, untrustworthy, fleeting, bait for the seven deadly sins?
One of the ideas I've been playing with is that everything we do, think and feel is just a habit. It's not always easy, but all habits can be changed. You work best depressed because you are in the habit of working best depressed. http://www.fallingawake.com/falling-awake-book-toc.html is an online book with a good chapter on habits (#9). It's all a bit new agey, but there are some good nuggets in there.
Above all, don't look at this as failure. This experience has given you valuable information that you can use in other attempts to feel better.
Thanks TW. Nobody's alone, right? Cheers!