Terminated Due To A False Positive On Pre-employment Urine Drug Screening?

I work for a few healthcare agencies that require a urine drug test for every new contract I accept. These urine drug screenings are usually done every 13 weeks. Recently I took a new contract that required me to do a urine drug screening, I came out negative like I usually do. However, my start date got pushed back and was made to do another urine test 5 days later. I was in utter shock when I found out it came out positive for an opiate. I spoke to the MRO and told her I don't do any drugs or take any sort of prescription medications. I was then told by the MRO that she'd have to report this to my employer. I spoke to my employer soon after and was reassured that I would still be able to work with them after I get it sorted out by doing a split specimen and deal with my state's board of licensure. Next day, I get an email that I was terminated...All these conversations with the MRO/employer were all via phone call by the way. I then proceeded that same day of my positive result to request for a split specimen to be tested to verify the first test. However, about a week later or so I find out the lab never sent out my specimen to another lab for re-analysis due to a "miscommunication". So that's still pending. I also decided to go to another different lab company (1 day later after positive results) to get a hair drug test and UDS done, all came out negative for drugs including opiates. I feel completely lost, having to deal with losing my job with said agency and possibly facing the boards regarding this situation. I have been given some advice from others to hire an employment lawyer or to speak to HR. I haven't reached out to none other than just a licensure lawyer as of now, that suggested for me to get the hair test/UDS done. I’d also like my job back :/ cause I know theres no way my urine would be dirty at all. I don’t do drugs whatsoever.

Note: I also was told by multiple people that poppy seeds could be a reason for a false positive? I was consuming poppy seeds in my foods during that second UDS. However, this was never brought up by the MRO. Of course I unknowingly was eating them without realizing it could be a potential issue.

Is there anything else I should do?

Location: Agency based in Arkansas