I would be very, very skeptical of a friend who felt so at ease diagnosing her friends. That's both bad medicine and bad friendship IMHO. Also, a psychiatrist is an MD (a psychologist is a PhD--although I guess you could have both.)

It sounds like you need to sit down with a good practitioner and spend a long time discussing your history including your propensity to abuse drugs/prescription meds. You need someone who won't be played (otherwise you will play them and be no further ahead) and really that's probably someone with skills/specialization in addiction. It may be that the best path to your wellness isn't a pharmacological one.