As I am reading your posts Kaiva, I get the feeling that maybe a break from the game will help you to calm down a little.

I'm usually not someone to suggest this, as I probably love this game just as much as you do and can understand that not playing it, even though you want to, is much to ask.
But really, I get kind of worried when I read what you write..because you really sound sad and dissapointed at yourself. This clearly isn't healthy for you.

And in no way I am saying that you should just give up at getting better, because if you keep at it you will surely improve. You already have.
BUT there are so many things more important in life than a high dps output or big numbers on FFLogs.
Ingame, you are so focused on your numbers right now that it will be hard to keep away from it and just focus on something else, of course you can try it, but habits are hard to fight most of the time.

So taking a break for like...maybe a week or so might help you to clear your head from everything. And then, when you come back, you might have a different view on things
Always remember that your health is the most important thing. Don't stress yourself so much that you don't enjoy playing anymore.
As some people already wrote, it's a game, not a reallife job.