That sounds a lot like ocd. Maybe look into symptoms and types of ocd

I would suggest therapy, meds, and a tool. Therapy because there may be a reason that your mind is thinking that way. A good therapist will be able to walk you through a couple of coping skills. Meds can be great! I am on a couple for my anxiety. What I mean by tools is basically coping skills. Mine is distracting my head or an activity that allows me to think through the thoughts which is great for my autism and easy with ADHD. Distraction could be getting a terrible thought and listen to music you really get into so the brain shuts down the thought because you got your jam on. For me, think it through is best with the overwhelming feelings so I will do art, cook, dance, etc. Something fun but allows your brain a slight comfort.

Take deep breaths (Count to 10) Listen to music/create playlist Meditate Write your your thoughts/journaling Art/painting Write down positive affirmations Protect your energy Minimize technology (Social Media Breaks) Face your fears RELAX!! Learn your triggers Boost self-esteem Express your thoughts/do not hold anything in Cry New hobbies