How does one approach their doctor about being diagnosed with ADHD?

I want to talk to my physician about ADHD, as I've always had problems focusing in cl, studying, and reading. I am away at a university, so I only have a limited time to be home to work this out. I would like to avoid seeing a shrink at all costs. Can my physician prescribe me medication for ADHD? Also, I have tried Adderall once before and Vyvanse once before, as my friends mother let me try them out. Vyvanse worked really well for me and allowed me to focus in cl, and yze everything presented while still staying attentive. I want to tell my doctor about Vyvanse working for me, without sounding like some teen looking to get my hands on some amphetamine pills. Any recommendations for my situation? What kinds of things should I say to my doctor? And would it be a bad to tell him how i tried the two medications? Thanks!