What are my options as far as a lawsuit if my boss at work disclosed and informed numerous co-workers the results of my drug test?

I was involved in a minor car accident on company time in a company vehicle. A few days later, my boss unexpectedly drove me to an office/lab and gave me an ultimatum of providing a urine sample for a drug test or being terminated. I obliged and consented to the drug test although I did not fill out any paper work or sign anything. My results came back positive for two different substances. My boss and I then came to an agreement that I would keep my job and I would consent to another test in 30 days. We also agreed at my request that I would strongly like to keep the results of the test confidential between him and I. Within a weeks time it was brought to my attention and clear to me that my boss disclosed my results of the drug test to numerous co-workers at great detail and length. Is this illegal and worth pursuing? I've since left the job due to the stress and general uncomfort of my privacy being violated to such a degree. Thanks.