A mindset is a set of deeply held beliefs that affect our behavior. A negative mindset cannot produce positive results. A term that describes this pattern is called rumination. This is a way of thinking that continually replays negative experiences or words.
I like to describe ruminating as free falling from a plane, unable to deploy the parachute. Just as a car is meant to fuel our fuel and our bodies are meant to run on food, we must learn to feed our minds with what it was designed for to learn to have something to live for.