Withdrawal are a very individual thing. Effexor and the one that did me in, Paxil, are the two worst for the most people, but any individual can have a hard time with any drug. It has nothing to do with the amount of serotonin you have. Serotonin, as far as anyone knows, has nothing to do with mental illness except for a very tiny population that can't make enough of it. You're not one of those. Effexor didn't make more serotonin, it changed the way you use what you have. It also did the same with norepenephrine. Your brain has to now learn how to function again without the drug. For some, this is easy peasy. For some it's moderate. For some, however, it's very difficult, and leads to what's called PAWS, which your doctors probably have never heard of, or Protracted Withdrawal Syndrome. The only way I know of to stop this is to go back on the Effexor at the last dose at which you felt fine and do a much slower taper off and hope that works. The taper has to be suited to the individual, not some generalized schedule a doc uses for everyone. Almost no docs do this, but it is the only scientifically accepted way to do it. Docs also are very bad at recognizing withdrawal, partly because almost everything they know about drugs is written by the pharmaceutical company. Anyone who disagrees with this is labeled out of the mainstream and ignored. It takes a very good psychiatrist to know this and work this way. Regular docs almost never know very much about the drugs they prescribe, as they don't specialize in anything and so are always jumping from one problem to the next, never really learning any of them completely except the simplest ones. The withdrawal you're feeling is thought to arise from the receptors in the brain that shut down while you were on the drug because they were no longer being used, as these drugs target just a certain set of receptors. The others are trying to wake up now, and aren't succeeding yet. The other way to do it is to wait it out and hope it goes away eventually. For most people, it does, for some, it never does. Let's assume you're most people and at some point, slowly, your brain will re-adapt to working naturally. If you don't buy that at some point, again, the only other way to handle it that I've found is to go back on the drug and try tapering off more slowly. In the meantime, try to stay busy, exercise, eat really really well, find what it is you look forward to and do that. Nobody can guarantee how this will turn out, so pretend it's all going to be fine -- life is full of pretense anyway so you might as well pretend optimistically. That's what cognitive therapy is all about, and what your therapist is trying to tell you -- you really are who you convince yourself you are, to some extent. I don't know if going on another medication will help or not -- I'm sure it does for some and not for others, but it won't work the same as Effexor so it won't do exactly what Effexor did -- they're all engineered to work differently or they wouldn't get patents. But if that becomes your only option, then it's worth a try. For me, I had a quack for a shrink, and needed to go back on Paxil and never did because nobody ever told me about withdrawal -- I eventually found out about it on the internet. At least you know, which I think will help you make your next move.
I feel like weeping just reading your post. I can relate, absolutely. I am into my fourth day of not taking this horrific medication and I am utterly miserable. The constant sobbing, inability to focus, the permanent and frequent 'brain zaps, disassociation, severe paranoia and exacerbated anxiety, profuse perspiration (predominantly at night). My depression has never been so alarming and intense.