Now I want to go college again after 3 months .but there is a fear of classmates they will be taunt

If you start with "fake" confidence, i.e. by being more outgoing, happy, smiley than you normally would, people will take to you. When that happens, you'll start getting real confidence. Don't overdo it, though. Just imagine what you'd feel comfortable with and push it just a little bit farther.