Can I file a law suit against my employeer?

I work for a large speciality Doctors practice. One of te senior partners ( A Cardo Doc who never lets you forget he is senior partner ) Tried to terminate me for accidently rooming a patient in a room he thought he was using. In front of several co - workers who hae all told management he was out of line and the way he treated me was uncalled for. He screamed at me, shouting at me to shut up, the look on his face, I was afraid he was going to hit me. Telling me this was his office nad he siuigns my pay checks. It was exteramly emotional for me, I wa sto have surgery 2 days later and it was canceled and now I need to see an cardo doc, becuause my ekg came back with a elevated heart rate. I am out on FMLA and can not return to work because they have hired a temp. I was reschedule dfor surgery in 3 weeks. I am afraid to return to my job, but my health insurance is through my employment. I believe this has cause a hostil work enviorment for me .