I had a similar thing happen to me once. It only happened once and at the time didn't even occur to me to think of stress. I "never" get physically sick so it was very odd to suddenly have a really high temperature and nothing else wrong (but the difficulty concentrating, etc. that a high temp brings) and to have it go away on it's own so quickly too.

Our bodies do funny things sometimes. I don't think it will pursue you but if it does, go visit your doctor, I'm sure we're probably not the only ones this has happened to (not that I put any faith in doctors to necessarily have a clue either but I would find it a little comforting if I at least tried with them).