Can I sue employer for discrimination and harassment?

I work at a convenient store for the past 4 months, I have 8 yrs experience store manager retail. I have been working really hard for minimum wage and even taking up the slack on extra shifts we are short. Another girl who also works as a clerk comes in late does nothing all day and leaves her messes for me to clean up after her just got promoted to assistant manager she did not earn this and has no experience she is also favored on what shifts she wants and I get the bad hours. She is very favored and it is very obvious. Today I asked her about some work she was supposed to do on her shift she got very angry and yelled and cursed at me for about 10 minutes following me around the store trying to provoke a physical fight. I was in the backroom working on the things she did not do on her shift that she was supposed to and she blocked my path after asking her to move 3 times she said make me. Our store manager was notified by myself of the situation and he does not care. Our store is monitored by video and audio and I can prove what she did. Can I sue my employer for discrimination and harassment? I cannot deal with this I am way nor qualified for the job she got and a better employer she was late every single day and didn't call and never does any work. I don't get it. Please help.