One of my biggest frustrations is having to get up for supplies (pen, highlighter, drug guide, review book, ect..) I bought a square plastic crate, and now before I start, I put everything I need in there, and keep my laptop close too. I've noticed that once everything is right where I need it, all the time, I get more done. I do better later at night, especially when I dont' have class the next day.
Study for an hour, then take a 10 minute break...repeat.
Reward yourself when you study like you want to!