I am having difficulty understanding what actually happened, but it is my understanding that you cannot take notes of anything during the test on anything that could leave the room with you. In doing the essay, you can write notes in the essay booklet but not on any piece of paper that you could possibly take out of the room. It is not just a issue of your having possibly brought the notes to the test but also that you are not supposed to reveal anything from the test to others after you leave and having notes with you when you leave raises that problem. That does not mean the proctor could not have used some judgment and done something less onerous, like allow to erase the notes before leaving, but the fact he instead chose the extreme option of dismissal does not necessarily mean you can claim he did wrong.
In any event, there is not much you can do. You did not finish the test and thus it will be canceled regardless of any complaint about the proctor or even if the proctor did wrong. You might be considering suing, but for what? To take the test again? CB will likely allow you to do that in Jan anyway. As a cancelled test, nothing will be reported by College Board about the test or your dismissal to any college.