3 weeks ago I became ill from what I think was food poisoning. I was vomiting for a day. Once gone, I am continuing to have a cramping pain in my upper right abdomen, I have cramping and gas pains accross my lower abdomen and I also have achiness on both side of my lower back. The pains are dull but are rather consistent and don't seem to go away. My appetite comes and goes. When I do eat the pain gets stronger after a few hours. Looking to know if food poisoning can last that long or if there is another problem unrelated?