I'm upset for no clear reason.

[CedarBranch]

This happens at random intervals.

If I could know why, my life might just get a little easier.
Maybe this is the source of my extreme pessimism, but I don't know ♥♥♥♥. Whatever it is, it makes me feel good about being negative (and self-destructive). That should NOT be right; nobody should feel good about that, but for some odd reason I feel I do. In complete honesty I want this to end, but I rarely show that that is what I want.

[NanTheDark]

The first step is admitting that something's wrong.

Now, you just need to make an effort, and you can change. It's not easy, but if you really want to do it, you can become a less pessimistic person and be overall happier.

[Kimonio]

Are you certain it isn't stress-induced or some sort of imbalance?

[CedarBranch]

It could be from making mistakes, but even then it feels like there's no point in being upset, yet I'll remain upset nevertheless.

[Dtroid]

Me too. I get upset sometimes,with no reason. How I cope with it is doing something else instead of just being sad.

[CedarBranch]

JJJ is upset = JJJ is irritated.

I don't mean upset as in "sad," but rather as being irritated/unsettled.
IIRC, "upset" has several different meanings, though sometimes I could be sad for no reason.

About doing something else... I thought I once mentioned somewhere that whenever I'm upset I don't want to be happy for the time being. It's true, unfortunately.