I want to know what I can do about being treated so badly at work?

My employer has told me that he hates me because people like me and he is my nemesis, he has called me a idiot, retard, dumb ass, has driven my customers away costing me money to support my family, he has screamed at me for things other employees have done, he screams at and belittles myself and other employees in front of customers and other employees. People get up and leave people quit, and I really needed a job and now I am in fear of losing my job, I dread going to work, and I feel threatened. I am not a manager, I have done nothing wrong, I am the 56th employee they have had and only been open a year, no one has worked there longer than 1 month due to how he treats people. Please help me.