Translated from Japanese: "When you're in a depressive state, the concept of "your future self" starts to fade away, leaving only "your current self" and "your past self" in existence. Since you can't form an image of the future, you lose the will to live, and all standards for action become bound by the "now" and the "past."
Savings, exercise, taking a bath, cleaning up—these things become hard to manage because you can't imagine "your future self." Your concentration fades too, so you "can't read books" or "take in what people are saying," which further lowers your self-esteem.
And when you're feeling down, you stop even realizing that you're in a "depressive state," so you mistakenly think "this is just normal," and end up unable to do anything at all.
People who only think about "the problem right in front of them" and "past failures" should be careful. When "your future self" becomes invisible, that's when a person has fallen into the swamp."