If you go through your life worrying about what everyone else thinks about you of course your going to be miserable. Concentrate on yourself and how you view yourself, your opinion should be the only thing that matteres to you. One of my favorite quotes: "don't let the clown with the frown get you down"
Try to write a list of how you think people view you now, then write a list of how you wan't to be viewed. Try to improve yourself for you and no one else.
Cheer up!