Dude just get sleep when you can. Those caffein drinks are garbage on the system. Nothing revitalizes and heals better than a good nights sleep. Sleep when you get home at night and study during the 4 hour lag. Funky schedule.
I don't drink coffee and I have cut out soft drinks, so give me 200mg of caffeine in a pill and I am good to go.
I just drink lots of coffee. About only time i ever have an energy drink is if im at a bar and get a red bull and vodka.