Sometimes a thought can feel like reality, rather than words your mind produced. It's called being fused to your thoughts. Loosening that grip is called defusion.
Type a thought that keeps hooking you, then get your hands on it. The more you push it around, the less it can push you.
Many of the ideas here come from the books of Russ Harris and Steven Hayes.
It will come back. Thoughts always do. What changed is that you held this one in your hands and felt how little it weighs. It's a string of words your mind makes, nothing you have to obey. When it turns up again, you'll know what to do with it. Thank your mind, and get on with your day.