Hello,
I experienced the same thing when I stopped taking Paxil. It was so bad that I considered returning but it was like choosing the lesser of two evils. But after several weeks what I call brain zaps disappeared. They are very alarming to get the sensation I had been jolted while getting up after sitting down a while. Like you I thought enough time had elapse and surely the paxil was out of my system but I think its more a result of the brains chemistry returning to function without the SSRI's.
Of course consult your doctor if you continue to be concerned. I found using a fast acting med like klonopin help relieved some of the withdrawal issues.