It's important you realize that stuff like adderall is useful in
studying for exams, but
not something you want to use when going in and taking the exam. You don't know how these drugs will effect you; under no circumstances ingest any unknown drug thinking it will help you during the exam. It will very likely do the opposite.
Many legal study aid supplements are out there, e.g. piracetam, hydergine, etc., but they're just that -- supplements. Don't expect drug-like effects from them. Desmopressin is a rather intersting one you might want to look into, as I personally found it the best of the so-called nootropics.
You won't find anything similar to amphetamine that is easy or legal to get. Remember, you still need to take the C&F, lol. If you're really interested in adderall or similar prescription stimulants, the best bet is through your university doctor. I'm sure you exhibit many signs of ADHD.
As a future lawyer, you should be well-versed in the art of deception and lying. This is exactly how many students get addy scripts, lol.