I reported my supvsr to HR b/c he was saying that i was sleeping w/coworkers, i got fired later for poor job p

his harrment was so bad that i had an anxiety attack at work and now that i was fired im still seeing a dr because of the stress he put me through spreading rumors and watching every move i did. i asked him why he didnt tell the other people to get to work and he stated that i wasnt the right race and that he will get rid of me in a wk, he did. he said this in his office with close doors so i have no proof. everyone knows how he treated me but when i called dept of labor they stated that in state of NC, employers are "at free will" and that they can treat u however they want, that i had the choice to leave my job. i was shocked that i received that email from NCDOL. now im spending my own monies for prescriptions for my nerves and hi blood pressure which i never had until all this started. is this fair? is it true that the law protects the employer for harrasment? i get off at 5pm, he would make mtgs p 5 and tell me i could not leave but no xtra pay. they dont pay OT