This is not adhd, nobody can stop thinking. I dont have adhd, i too have this.

Your brain can also not work above like 5% simultaneously, or you literally die.

But i get the frustration nonetheless. The trick is to try and focus on sonething else, like breathing, this is why mindfullness exist.

Though i do see people with adhd struggle to "focus" on "something else" so I guess the point still stands.