Part of my problem was I was wondering if I was out of line for how strongly I feel about not having a party this year. I suppose that's just part of my anxiety disorder: always second-guessing everything, even my own feelings.
All of my close friends know my feelings on surprise parties, but there are a few (newer) friends who might try to throw one for me without realizing the issues it would cause.
I would drop some comments about your feelings on surprise parties so that they know. It could ruin a friendship if you chose to walk out of a surprise party when their intentions were to be celebratory, not PA.