I agree with Jack to practice what you're going to say,, and how you will say it. By the time I got a job, I had gone on so many "practice" interviews that I had it down pat. I figured out what to say, and what not to say the hard way.. by getting rejections.
First of all, don't feel bad if they don't hire you,, and don't give up if they don't hire you... There IS a better job out there for you. If you feel like you're just stuck at your job now,,, keep looking, there will be a job for you.
I learned to talk for a few minutes and answer a few of their questions about myself,, and once I feel like they've gotten to know me a little bit,, you know, experience,, attitude,, etc.. then I would start on the recovery program thing. I would say something like...
"do you know about the program TPAPN?'" if they say no,, then I would explain what the program is about,, going into details about drug testing etc..
Never volunteer the story of how you got into recovery,, like what you did to get caught, etc. I found that some interviewers would ask me just because they were nosey, and never intended to hire me in the first place. I learned quick who those people were. If they say there's no position available right now,, then smile and be professional and leave.. I had one lady tell me AFTER I seen the posting on the wall of all the positions available,, that they didn't have any available right now,, then she asked me what I did to get into recovery. The nerve of this lady... I didn't get the job and she was still nosy as heck.
Anyway, I wish you all the luck! We all deserve to have a job that makes us happy..
and no one should be stuck in a job that sucks.