I read a lot of philosophy until I had an existential crisis, which ironically made me feel worse at first and then better later on, because I realised basically "nothing really matters" and the majority of things that stressed me out are so small. Sure, some stuff has negative consequences for me and messes with my emotions, but even that passes with time and much of it is simply in my head (I got a nice cocktail of ADHD with depression and anxiety and get stuck in feelings of dread and doom).

Well, I also go to therapy, and there I learned to focus on myself and what I need and like, with the goal to either distract myself or enjoy small pleasures. Like I walk to a quiet place somewhere when noise stresses me out or listen to music, I make myself a nice meal or some tea (iced tea in summer) or take a cool shower or sit down to draw something or write comments or talk to a person I like, all those small things that make me feel a bit like "I can live one day longer".

Basically, instead of looking at the world and the things you can‘t change of affect like your past, look only at yourself in the here and now and ask "how could I make this a bit more bearable for myself?" and then I do that. Though there is some limit there like don‘t do drugs (which I DID do, it gave relief, but made me feel much worse over time! just a warning), but even outside of that there is usually something you can do.

Many desires are also artificially induced by marketing and peer pressure and the more I understood that, the less I felt like I had to do x or y or whatever everyone else is doing to be happy. That includes my comment and those of all others by the way, one or more points may resonate with you and help and others may be completely useless to you, what matters most here is finding what works for you and doing more of that. If you try some of this and have a moment where your mind calms down and you feel alright, take note of that and do that again.

Though I‘m not entirely well, this stuff comes back sometimes, but I got a bunch of ways to deal with it now which help me out.