Amphetamine questions.

Patient: I think this is the right subject. I recently thought I had add because I did the research online and asked alot of my friends and elders and with the evidence I came up with Idecided that I was correct. So my dillema is that one of my friends gave me a pill and said to see how it works and the label on the bottle was “-amphetame SLT XR 15 MG” and underneath in small print read: “substituted for adderall XR”. so I tried it and obtained the results I was looking for, I was able to focus on the task at hand with out day dreaming about my favorite video game or wondering what was next or thinking about all the other things I had to do and quite frankly my day went great. People commented on the improvement in my attitude, etc. So my two questions are: first, how do I get tested by a profesional to see if this is something I should get prescribed for and two, will I test positive for amphetamines if my work calls for random drug tests. I thank whoever it is that responds to this for your time.