I Had ADD As A Child And Now ADHD Is

I had ADD as a child and now ADHD is affecting my job and life. I don't tell any doctors what I need, for being seen as a abuser. I can't stay focused nor complete task fully without starting something else. My job is highly dangerous for myself and the people I work with. I self medicated one time with adderall for a short period time and I was alert, and 100% attentive. I stopped cause of my jobs drug screen requirements. What I need is how I can get a prescription so I won't chance losing my job?