All-or-nothing thinking is a cognitive distortion. You see the world in black or white and cannot see the gray.

I sometimes think this way. When I notice that I'm fixated on something I try to think of what was the situation/trigger that made me think of it in the first place. Then I write my feelings when I first became fixated. Then I write my thoughts when I first became fixated. Then I look for cognitive distortions (all-or-nothing thinking, catastrophizing, jumping to conclusions, etc.). Then I write a list of the evidence that supports my thought. Then I write a list of the evidence that does not support my thought. Then I conclude if the evidence supports my thought or not (that will be the thought I choose to believe). Then I create an action plan (how will I act on my conclusion).

99% of the time this method exposes the gray area for me.