Do you still have your gallbladder? The reason I ask is that the pain you're experiencing, along with the headache, could be a gallbladder attack. I'd never had an attack as far as I knew when I had a week of being in really bad pain and nauseated. I never ran a fever, and didn't have other symptoms, but I did have a headache.

I ended up having emergency surgery!

Just keep it in mind.