I am in the Army and most likely going to recieve an OTH for failing one urinalysis for MDMA.?

I want to enroll in a nursing program asap. I also wanted to get a lawyer and seek upgrading my OTH. I had a clean record, made my E5 at 21 with 3 years in service. I had a one time incident and tried to self refer myself to ASAP. My NCO did not let me finish the program, and 3 months later I failed the UA. Please help with any comments, no negative comments please