My motives were exposed, crushed, and I am now backed into a corner...

My manager handed me some files to review and after she explained them, as she was leaving, she quickly turned and said, "And, I expect to see you at our Holiday Party. It is important that you go. It's going to be fun." She then walked away before I could say anything. I wouldn't have even known what to say and have no idea how she even knew I was pondering how to get out of going.

I am as social as everyone else, but I have been trying to figure out a way to get out of going. Now, that doesn't seem possible. I hate these kinds of social gatherings, and I don't even know where she got the idea I wasn't going to show up. This is problematic.