Thanks for sharing. Good job on the paper. Nice explanation.
If you want a technical critique, I would assume that the grading came down because of the closing paragraphs. I understood your explanation, but the teacher might have found the explanation of the history with your "friend" hard to follow. All the first part was very clear, easy to understand, personal, yet thoughtful. When you regressed to the betrayal in the closing paragraphs, it seemed rather rushed and emotional, after the careful and analytical first part. I'm guessing that you cut some content there to fit it under the required number of pages. That's what I'm guessing, because that's what I would often do when trying to squeeze more into less space. But very well done. Much better than many of the papers I had to peer review in my English classes.