I don’t think there a single feeling that corresponds to “difficulty concentrating”.
If I’m very tired then I have difficulty concentrating, but that’s very different than the feeling of my mind being distract by topic A when I want to think about topic B.
I don’t think there a single feeling that corresponds to “difficulty concentrating”. If I’m very tired then I have difficulty concentrating, but that’s very different than the feeling of my mind being distract by topic A when I want to think about topic B.