So, after Providence, I decided to actually go and have a picture taken of my ankle, based on Kathy's advice. As it turns out, I have an avulsion fracture on the tip of my lateral malleolus.
When I rolled my ankle at Providence, the tendon pulled so hard that it separated a piece of bone from the tip of my left ankle with it. It's a small piece, and won't reattach. After seeing an orthopedic specialist, I am in a small air cast for stability, and have been advised against racing (actually running, but for 'cross, that means racing) for four weeks. Guess this is as good a time as any for a "break" ;).