A tired mind can turn a small problem into a philosophy about your entire life.

Fatigue does not just lower your energy, it changes the size of what you are looking at. A small setback becomes evidence about your character, a difficult conversation becomes proof about a whole relationship, one bad day becomes a statement about your life. The thoughts feel unusually clear while this is happening, which is precisely what makes them convincing and unreliable at the same time.

Notice when your thinking starts generalising, especially late at night. Treat sweeping conclusions reached while tired as provisional rather than true. Sleep first, and see which of them are still there in the morning.