I have been on Lamictal for about 2 years (in combinatin with zoloft and wellbutrin). It was the first mood-stabilizer I tried after my psychiatrist changed my diagnosis from major depressive disorder to bipolar type I (mainly depression, with few manic episodes).
I gradually went up to 200mg at the start, and it was way too much for me. He also put me on lithium but I too started to feel detached and a bit robotic, and just 'foggy'. After a few months I weaned myself off the lithium and went down to 150mg of Lamactil which I'm on now.
Maybe you need to get some clarification from you doctor because as I understand it, Lamactil and Depakote are both mood stabilizers for bipolar disorder. But if you suffer from anxiety maybe you should be looking for a med that acts more on dopamine? I think there's been a huge increase in diagnoses of bipolar disorder because sometimes its hard to distinguish anxiety from mania sometimes. Most of my manic episodes were induced by SSRIs, made worse by caffeine, just as you mentioned. But the mania was distinctly VERY different to my feelings of anxiety and panic attacks (i.e. uncontrolled euphoria vs paralyzing fear).
This is my own opinion, I'm not a doctor, but what concerns me about Lamactil is that the doctors aren't really sure how it works, just exactly which neural transmitters it stimulates. But I continue to take it as a mood stabilizer as I find it has less side effects than lithium.
You might have similiar experiences as you did yesterday as you withdraw from Lamactil and begin Depakote - sometimes Extended Release meds can be quite powerful and disruptive initially and interact with whatever else you're taking.
I usually experience what you have whenever I switch meds, increase doses or try to withdraw from the Extended Release ones (zoloft and effexor). Feeling detached, 'outside of myself', extreme vertigo, 'brain shivers', vomiting and dizziness. When it happnes, I try to 'embrace' it (maybe not for the vomiting!), to accept it, and know that it will soon pass.
The best thing that worked for me was taking a very small dose of drammamine (OTC sea-sickness pill) it helps with dizziness and nausea. Or else, I try to wean myself off the drugs more slowly.
Sorry this is so long. I hope that the adjustment continues to go smoothly, it is excellent you're managing to avoid the caffeine, that is very important, and its one addiction I've never been able to quit!