I am sorry to propose this, but are you pms'ing? You sound like me for half my lufe, where one day everything was absolute shyte, and the next day, everything was roses. Same jobs, same marital status (whether i was married or single), same bank balance - only difference was my period started and i was now as happy as i was miserable the day before.

I think maybe neither emotional state should have been considered "reality." They are both drug - or rather hormone - induced. Sounds like you might have gone back to the job on a high.