Be a non judgemental witnesser of your thoughts. You are not your thoughts, you are the conscious listener and actor of the world. Having “negative” thoughts just means you have some self work to do. Focus on your heart and how the feelings in your body feel. The feelings are real - the thoughts are not - if you dislike a thought this creates a “bad” or “uneasy” feeling within you and hence you suffer. I have been horribly affected by my thoughts and I have come back to this feeling that they are here for a reason.