If you are college age and have an M3 then someone obviously bought it for you. So its pretty simple: If that someone is paying for your med school tuition, room, board, food, insurance, gas, maintenance, etc, then keep the car. BUT, if you have to foot the bill and put your own food on the table, then sell that sweet mofo and get a beater. Do NOT take on loan debt and keep an expensive car at the same time--it will bury you. I sense that your situation is the former, though...
Delay your gratification, its all the sweeter (and its a better survival skill).
And don't let people put you off on the profession. I still LOVE what I do.
2008 M3 Coupe / DCT
// StopTech BBK 380/355 / Pagid RS29 / Motul / Apex Arc-8 / BFG R1S / Ground Control / MS filter / Performance spoiler / BPM tune // Road Atlanta 1:39.80 / VIR Full 2:10.87 / Barber 1:42.20