You are allowing an unhappy history to color your present life. You might benefit from playing cds of positive affirmations, reading them, and/or repeating them on a daily basis. I find them quite helpful and have used them off and on to help myself feel better about myself. Another thing I do is smile and greet people where it is appropriate. While I stand at the bus stop, when someone sits next to me on the bus, when I come into the building at work. If you express a confidant, joyful attitude it tends to attract the same in other people. I have come into a room and overheard others talking bad stuff about me; I didn't do anything about it except ignore it. Some people have bad manners. Focus on being a good person and making friends with other good people and those ill-mannered people will fade in significance to you. Courage!