I'd say, if your account is pretty much locked, and they're aware that you are trying to do stuff such as that, that you should probably stop trying. If your school's computer/network administration has any idea of what they're doing, there's not much you can do. If they're doing it right, then they probably are alerted of who's trying to access blocked content/use proxies, and when and where they did it from (if it becomes a regular occurrence). If they know what they're doing and they are knowledgeable about how to do it, the administration can be like Big Brother.

And how much free time do you have in high school, exactly?

Edit: not to encourage your lack of motivation in academic progress, but using a phone or other device as a tethered connection, or using an external wireless connection, circumvents the school's filters and blocks altogether. You probably can't use either of these on the school's computers, though, so you'd have to use a laptop.

Believe it or not, however, you're supposed to be learning in school