oh sally, i'm sorry this episode happened.
i don't know what methyl B12 is. you might consider stopping 1 to see if it makes a difference for you. if it does you'll know the other is ok. if not then stop the other.
if this con'ts another few days to a wk i'd call your dr. since it's such a change i think it warrants a phone call.
i'm sending healing prayers your way.