Severe pain in my stomach between rib cage, had fever 2 days ago but its gone, nausea, constipation, lack of digestion. (thought it was food poisoning but its not because I was the only one)?

? Influenza. The current strains of flu have been associated with some GI symptoms. It sounds like you may have encountered one. The fever points to an infectious process, regardless until proven otherwise. As long as you are improving, i would not be too concerned. Some acute processes include your symptoms but in a much different order.
Gastritis. A viral infection of the GI tract usually has symptoms of nausea, vomiting and diarrhea. You may have gastritis(inflammation of the stomach lining). Follow a bland diet and try taking mylanta for relief. Inflammation of the gall bladder from stones, pancreatitis or hepatitis are less likely, but get examined if symptoms worsen or don't subside.