Is there really a bank open that many hours in a week? For me personally, I get overwhelmed even working part time, but everyone handles things differently. I really recommend watching this video:
It helped me learn how to study efficiently. But really, my biggest advice is to prioritize. If you care about getting into medical school, obviously studying and grades are going to important so I'd cut back your hours on your job if you can. With that many hours, I can't imagine how you would have time for volunteering, hobbies, research, sleep, even a social life...Worst case scenario, take a light class load and limit your semesters to two science classes and electives or LE requirements (depending on the school you go to) and study in between classes and your job.