From what i've been told, the Wellbutrin is mainly for depression. Most of the people I know that have tried it for anxiety/panic said it didn't work for them at all. It made them more anxious. I believe this is why they give it to people who are already on SSRI's that have no motivation, sex drive, etc. It's supposed to "up" your mood & energy. I may be wrong, but this is what i've heard.
On the flip side, I have to say that i've had great luck with Zoloft. I have GAD & Panic Disorder (25 years now). I have been taking it, on and off, for the last 10 years or so. I just went back on it a little over 3 weeks ago, due to starting perimenopause, my attacks got crazy out of control. Maybe you should try a different med. There's Zoloft, Lexapro, Effexor, Cymbalta, etc....I'm sure there's something out there that will work long term for you, maybe with the combination of medicine and therapy you'll get the relief you seek. But for me CBT, self help books, counseling, and all that never worked, the only thing that works is the medication. So i'm a lifer now.
Anyway, I hope you find something that works for you, and stops "crashing out" on you. Good Luck! Fox