Minutes long euphoric episodes?

Make an appointment with a doctor and explain your symptoms to get a proper diagnosis. It sounds like from your brief description that you might have some telltale bipolar symptoms, the euphoric mania and the depressive lows. These usually alternate and can result in the mood swings that characterize this illness. But don't take my word for it, I don't know your personal medical history to be able to give you a proper diagnosis. Definitely make an appointment with a doctor. Hope this helps, good luck.