Arrested for DUI-other after failing field sobriety test no breathalyzer was given. Do they have a legitimate case?

Charged with DUI- other substance which impaired such person's ability to operate a motor vehicle, not DUI-other; any drug or controlled substance, the possession of which is unlawful under the MS Controlled Substances LawUpon search of vehicle officer found air hose nozzle and bottle with ashes in it in my possession, which they claimed was paraphernalia. After being released I went to urgent care clinic and voluntarily took breathalyzer and drug screen which both came back clear. Do they have a case against me and with lawyer is it possible to get case dismissed based on these results as proof that I was not impaired at time of arrest? I am DOT regulated and am concerned that I may lose my job if I am found guilty of these charges. What should I do to further strengthen my case to prove I was not impaired?