You have given a very good description of what I experienced. For me, it seemed to be from my anti depressant. I was not taking it regularly and this was the side effect. Once in a blue moon I still get it but not as bad as I was. The anti depressant seems to be the best scenario so far. Because I have M.S., docs did not explore it further and it seemed to get better. Having M.S. seems to be the blame for everything! However; doing my own research and talking to docs: antidepressants can do this if you go into a withdrawl type situation. Please keep me posted if you find something more. You can private message me on this site. Good luck to you