Stick to a tight schedule, I guess? Make a list of things you have to do, put in a break somewhere, and then set the alarm and stick by it. It takes a lot of willpower, but then if you finish all of the things you have to do, you can reward yourself properly.
don't sweat it! when your watching movies think about the camera angles, script, acting and so on, study it, now when your watching movies you can say "i'm researching". Spending alot of time on facebook? then think about what people are posting, now you can call it social studies. snack break? haha that's just food testing you could write a short critique after eating it. Believe it or not there are people out there who actually get paid to these kinds of activities, so long as your using your brain slacking off can be called 'work'