Sorry, I can't help with a medical diagnosis but it does sound like someone twa**ed you with a good left hook at some point in the past.
Given that you seem to have little recollection of said incident I would assume you were malletted at the time and probably trying to get your evil way with his wife / girlfriend / daughter or possibly, if you were that hammered, his mother!
Been to any weddings or similar get-togethers involving copious amounts of falling over juice recently?
