Here's my opinion, and it might seem harsh, BUT, your teacher told you not to use the Spark Notes, and you did. You got caught, you deserve a 0. It doesn't matter that everyone else used them, the rule is the rule, you broke it, you have to suffer the consequences.
That being said, I think you have an opportunity to mitigate the consequences. Meet with the teacher, tell the truth about how you used the notes, and ask if you can re-write the paper. Is it possible to re-write the paper using a different theory or premise? It might be too late, but I would still give it a shot.
Finally, make sure you and your mother are on the same page on this. She needs to have all the information, so she doesn't go into the meeting, guns blazing about how you have been mis-treated, and then feel silly when she hears the truth. I might also suggest you leave your mother out of this all-together, and handle it on your own, if you feel comfortable about it.
Good luck.
Denae
Once again, I didn't use Sparknotes in the way he forbade. He said do not use them to write your report. I didn't do that. Technically, I didn't break the rule.
I have to disagree with "theft of ideas". For example the main character lives in a hotel during some of the book. Well, that's a fact. The author of the Notes didn't conjure it up. It was lifted from the book. Therefore, I'm not stealing the author's idea. We both got it from the same source - the book. It's not an "idea", it's what's printed there.
By a few hints, I meant during the summary section, a few of the words felt "sparknotes-ish" for my mom (other members who read it didn't notice anything); not the analysis which was more then 100% personal, NOTHING from Sparknotes.
I'm not sure about anyone else in this thread, but it sounds like a few of us know our stuff. 