How should a highly sensitive person deal with insults or with people being rude?

Everytime someone hurts me emotionally I just want to bring out my fist and hurt them because I feel I can't defend myself emotionally but I can substitue sadness for anger. I grew up being the "nice boy" and so people never insulted me in front of my face (but people did talk about me behind my back) so I never grew up with the experience to be tough. I'm nice to people but I know that sometime in my life there will be jerks who bother me for no reason and I don't like getting angry or violent but I just don't know how to deal with people's rudeness or insults. I am usually very self conscious about things and I am very empathetic about others, I've had trouble making friends in the past because I have major trust issues and I felt that people would hurt me. I know now that most people will be good to me if I am good to them but how do I deal with those who are bad to others for no reason?