How in the FUCK do I stop getting distracted when studying??

I'm a recovering addict which means I'm not supposed to take stimulants to treat my ADHD, so I've just been taking Straterra and have yet to experience any benefits. (Hopefully at a higher dose that will be different.)

That being said, I am HORRIBLY distracted CONSTANTLY when doing homework. I'm trying to stop picking up my phone or opening Facebook on my laptop or start making food I'm not that hungry for, but I'm having such a hard time.

Even this is a distraction. It's been three hours since I sat down to study and I haven't even finished two chapters for my ethics class, and I have a lot more to do, most of which I won't have time for because I need to sleep and have class in the morning.

HELP! I don't think I can keep up with as many classes as I i have (which is only 3, but I also work full time and go to Narcotics Anonymous meetings 4-5 times a week), so I'm thinking of dropping one, but I'd really like not to have to.