@Morgane IME: anxiety in particular is, mostly, out-of-whack brain & body chemistry.
Keeping that in mind has helped me cope with it. E.g. when I'm feeling anxious, I try to do some light physical activity: that puts the adrenaline to use & can help defuse my brain.
But it's taken years of dealing with that (and depression and low self-esteem) to get better at symptom management. Not letting the brain weasels nest, or at least not for long.
I hope you find your own ways to cope 💖