I know where you're coming from. A while ago I did a 30 day, no forum, no blog surfing trial. Which worked great, and afterwards I surfed much less too. But lately I have began to surf much more again.
The internet is a bit like TV. It's easy entertainment that requires very little effort on your part, and there are always new and interesting things to be found there, which is why it is so addictive.
You have both your school and a library you can access the internet at, and probably some internet cafe's or wireless hotspots near by. So why not get rid of it at home. You could try for 30 days.
I'm actually considering canceling my interent at home. I have an internet cafe just down the street, and my job is 5 min away. I don't really need it at home. I once was without internet at home for a couple of weeks, because the phone company messed up some cabling in my building, and I wrote a small computer game in my free time during those weeks. When I needed the internet I would go to the cafe, but then I also had a list of things I needed to do on the net, so it would rarely take more than an hour.
Of course, it helps to have a laptop.
