Fever, Stomach Pain, Nausea, Abdominal Pain. Any Idea?

One week ago I began to feel fever and stomach pains at the end of the workday around 4-5pm. By the time i made it home around 7:30 i could do nothing but kick my shoes off and fall into bed. I could not move due to intense stomach pains and high fever. The next day it was all I could do to get up to refill my water bottle and force myself to drink. I never felt any intense urge to vomit , but eating was out of the question due to intense stomach pain. Towards the end of the day it finally occurred to me to take my temperature - 101.7 On day two I managed to eat one piece of plain bread and more water. Temp remained consistent between 101.5-101.7 - Intense abdominal pain Day three - same fever and pain levels, I manage two pieces of bread though. Day four - fever at 101.3-101.5, slightly less pain. Two pieces of toast and a couple sips of soup. Day five - fever breaks but stays at 100. Stomach pain starts to abate. I eat a whole can of soup and try a plain grilled chicken sandwich and then cereal but can t touch either. Day six - fever at 100, pain significantly less, I manage half a sandwich and more soup Day 7 - Today, fever between 99-100. Toast and half a sandwich. This is the worst illness I have ever had. I caught it from my sister who had just flown to visit from NY. She got better in 5-6 days though, and though I also feel much better than the first 3 or 4 days I am still not feeling that this thing is leaving me completely. I can t find anything that presents such a prolonged fever, abdominal pain but no urge to vomit, and never any congestion or respiratory problems. Any idea what it is? Thank you.