You may not have done nearly as badly as your scores would claim, actually. Filling in bubbles at random (or down a single column, or in any pattern whatsover) you would expect to get 25% correct in every section. Getting a zero is pretty miraculous in fact.
I assume you didn't leave all the reading bubbles blank, but it looks suspiciously like you had some persistent problem with how you filled in the bubbles (not pressing hard enough, a pencil type that is hard to read, smudges that make it look like multiple answers are filled in... ).
Since it's unlikely that problem happened -only- in the reading section, you may also have scored much higher in the other sections as well and just been better enough with your bubble method that some of the answers registered.
If you take the test again, make sure to bring a high-quality eraser and not rely on those stupid nubs on your pencil, and also bring the softest allowable pencil (it'll mark darker and easier). I don't like mechanical pencils either for these tests because they make such thin lines it's harder to fill in the bubbles completely unless you spend a lot of time at it. (Okay a second or two more, but multiply that out over the number of questions on the test and it becomes valuable minutes!)