Devito Restaurant: defamation, slander and discrimination law suit...possible?

I was approached by a superior while in the presence of other employees and told that I smelled like smoke. 3 hours later in front of other employees I was told I was being written up and sent home for being "too f*cked up" to work. I of course protested stating how obvious it was that I was completely sober. I was told to leave work anyway and was suspended for one day. At no point was I drug tested despite my offering to take one.

The restaurant is not a drug-free work place (meaning they don't require a pre-employment drug screening nor a signature among the new hire paperwork agreeing to drug free work place terms), so can I be written-up and suspended from work on the suspicion that I am intoxicated especially when absolutely nothing about my behavior indicated impairment? If I was suspected of drug use should I have immediately been drug tested to substantiate or disprove these claims before disciplinary action was taken and before my name was slandered publicly in the workplace?

My employer knowingly lied about my physical condition in the write-up. I was on camera the entire time, the footage will show my behavior was not that of an intoxicated person as well as the statements of other employees who observed me.

After the one day suspension I was called back to work. A meeting was held before my shift in which I was told I could continue my employment there. I again offered to take a drug test and again my supervisors declined. At the conclusion of the meeting I stated the the information in the write up were lies purposefully concocted to undermine my employment due to the supervisors biases. I was then fired.

I was the only black person working outside of the kitchen. I also am female, although the supervisor who began this issue is also female, she has a history of discriminating against and targeting other females. There are several other employees who can attest to this.