How do I train myself to control my temper?

I live alone, & I'm usually home all the time because of my disability. I'm on the verge of homeless & will be FORCED to DEAL with people. I'm highly sensitive & have been hurt all my life. People are always rude to me & talk to me like they think they have a position of authority over me. I'm generally a nice, kind, caring, loving person, but I can't handle being talked to harshly everywhere I go. I'm a loner & not a people-person. All day today, people have been rude & unhelpful to me when I was making phone calls, inquiring about a shelter to stay in. I almost cursed a few of them out.