When I Was Younger (10-11) Years Old I Use To

When I was younger (10-11) years old I use to take medicine to help me with my behavior (never could focus). As I got older I stopped taking it because it was embarrassing and now that I am in graduate school I have a hard time focusing to get the grades that I deserve. I study for 3-4 hours daily and seem to very little from small distractions. What can help me?