you honestly just need to go to a nice ghetto or have a friend who swindles doctors.
i knew this one like overweight kid who smoked weed and cigs. Kid was just massive in size, and anyone in their right mind would say walk it off fatty. But he had a pretty terrible cough. He was able to basically convince his doctor that besides tramadol, he also needed liquid codeine because it helped him get to bed, and he couldn't sleep because of his cough.
cliffnotes - you can get cool drugs from doctors, but your parents will only think you are all the more weird since you need a cocktail of drugs just to function (as the doctor says....but you are just telling the doctor what he needs to hear to diagnose you with whatever you want)