How To Reach The "Next Level" of Mathematics
I just wanted to mention a possible resource. You could look at the mathematics section of the MIT open courseware.
Specifically they have video lectures for an introduction to calculus, multivariable calculus and linear algebra. (probably some more too) One benefit is that it is not too difficult to motivate oneself to watch a video.
You should start with their introduction to calculus: http://ocw.mit.edu/courses/mathematics/18-01-single-variable-calculus-fall-2006/video-lectures/
If this is at too high a level for you right now, keep it in mind for the future.
Use MIT open courseware - it's awesome! Also use Khan Academy, its incredible!
Given that the original poster said he/she was a Junior High student taking prealgebra, almost all of the comments and answers currently visible to me seem highly inappropriate.
perl.j --- I recommend looking for the following books in your school library or public library:
Danica McKellar's 3 books (if you're a girl)
http://www.amazon.com/Danica-McKellar/e/B001JP7Z7G/
Mathematics, Its Magic and Mastery by Aaron Bakst
http://www.amazon.com/dp/0442005288
Mathematics for the Million by Lancelot Hogben
http://www.amazon.com/dp/039331071X
Realm of Numbers by Isaac Asimov
http://www.amazon.com/dp/0395065666
Realm of Algebra by Isaac Asimov
http://www.amazon.com/dp/0449243982
(November 4) I looked at these books last night and now I don't believe Lancelot Hogben's book belongs with the other books I listed, but I'll leave Hogben's book here anyway.