Are you talking about “awfullizing?” I often imagine terrible things happening during very normal situations. I used to do this while driving. I kept imagining accidents happening. I finally started telling myself that I didn’t have the power to predict the future nor to control the actions of others. Staying present and controlling my own behaviors would help me avoid accidents or at least limit their impact more effectively than “awfullizing” or thinking “what if,” should they occur. In short, reminding myself to live in the present because the future and the past exists only in our minds helps me tremendously.