When anyone says anything remotely negative or criticizes me in even the slightest way my mind repeats what was said for days or weeks, how can i stop?

Obsessive: Psychotherapy would be very beneficial. It can be with a clergy person, social worker, psychologist, behavior therapist , or psychiatrist. It can be at a community mental health clinic or a private office. To feel better, you should get some help.

Compliment others: Try this...Each day give a heart felt compliment to 1 or 2 people each day. Before long you will build up your own self confidence. Little remarks spoken about you will mean very little because you are a better person. All the best!