nausea and fever feel like I have been hit by a bus...

Hi I need some help on the way I have been feeling recently. It started on christmas morning, i had really bad nausea and stomach cramps. I felt like i could vomit at any minute but it never happened. I had no appetite and couldn't eat anything without feeling sick. I also had a fever. The following two days I felt fine. Appetite had returned and I was just a little tired. On wednesday i had to leave work early as the nausea and fever was back. Again this disappeared and since wednesday I have been exhausted, falling alseep during the day which is not like me at all. I also feel like I have been hit by a bus, every muscle in my body aches! I have also had a terrible headache that won't subside. This has been going on for 6 days now, and a family member has felt the same. Is there some sort of virus going around causing thee symptom? I even done a pregnancy test which was negative.