Could be just what you say it is. A fever and nothing but a fever. Get some rest and see if it does away. If it doesn't go away in one or two days I would suggest seeing your doctor. My guess is that it could be a pretty bad cold that you just need a little attention for or maybe it could be the start of Mono. My mono started out as a fever for a few weeks to a month (I know! I had a fever for almost a month!) Until I started getting a sore throat and all that other bad stuff until I was actually diagnosed. Take your time, get some good rest, and if it stays and doesn't get better I would see a doctor.