An hour ago i was feeling really down, and just now, i was randomly walking around my room with headphones on listening to music, lost in thought like i often do for quite some time now to take my mind off things, and it was like a random dopamine hit out of the blue.
I never had that before, had to sit down for a moment because i was feeling so happy and excited.

I'm not on any medication and i do not take other mind altering substances.
I noticed that recently i have been experiencing mood swings, feeling "depressed" for a certain period of time and then feeling content, although the periods are quite irregular and the down phases outweigh the up phases i think.

Is this a sign of mental illness or an abnormality?