Your brain generates thoughts automatically, and their appearance does not make them true. Trying to suppress a thought can keep your attention fixed on it. Instead, notice it and say, 'I am having the thought that…' Then ask what belief the thought represents and whether the evidence fully supports it. You can allow the thought to be present without obeying it, and redirect your attention toward a more reasonable belief or useful action.
Three Breaths
Breathe — Notice the thought without trying to suppress it.
Breathe — Say to yourself, “I am having the thought that…”
Breathe — Ask what belief it rests on, then choose a more reasonable one.