This sounds like hypo/mania to me. I know you said you don't have the pressured speech, delusions, etc. but I don't think you necessarily have to have every symptom to be in an episode, especially if it's just starting. From my experience, I get exactly what you are describing before skyrocketing up towards further euphoria, and then come the racing thoughts, fast speech, high energy, etc. I'd say to continue monitoring how you feel.