Hello! i must admit from what you've described you sound quite alot like me!
Just a few comments, as i really need sleep right now...!
How important is it that you have internet access? You say its to do background research? Now i would and have argued the same thing with my parents in the past but to be completely honest background research to me at least is just another way of getting distracted. I always find that i start with the best of intentions of researching the subject at hand but then going off on a tangent, things i dont need to learns about always seem alot more interesting than those that do. If you're the same, think about how important the background research. If you're not, ignore that point completely!
Secondly, re giving up the graphics... that depends how important it is to you in the long term. If you have visions of being a graphics god with a high flying career in graphics i'd advise against it. If not to be completely honest I'd put it to the bottom of the pile behind subjects that are more important to you.
It's a long time since i did GCSEs, when abouts do your exams start?
Are you still at school now or on study leave? If you're on study leave and if possible it might be worth going into school anyway and working in the library? I know it doesn't sound appealing but firstly it'll make sure you get started at a set time and secondly theres alot less distractions.
It's late, I'll come back tomorrow and see if i can think up any more wisdom!