ah....I remember this time. Getting good GPA to get into good post secondary opportunities.
Well, my suggestion is to tell her straight up what was your problem. Most teachers understand. After all, we're only what, 17, 18, 19? We're still learning. Tell her you can't afford to have this mark and fulfill your post-sec goal's. Tell her you've never enountered something like this, and it'll never happen again.
being in Canada, i'm not really sure what AP is, so...yeah;
I hope that helps.