I have heard so many patients describe this same symptom complex...sometimes when starting a new med, sometimes when stopping it. There is no exact explanation other than the medication does effect the brain in various ways, this being one of them as a side effect of the beneficial effects. You were right to stop this medication.
Okay I have stopped Celexa and the weird symptoms have stopped. But I went back to Clomipramine along with clonazepam. I find it very strange that the symptoms I had while on Celexa was never explained. Thank God they have stopped. Now all I have is like a tight band around my head along with a dull headache.