Continuous lower abdominal pain, recurring fever, vomiting, gurgling in stomach, weight gain, excessive hunger and thirst, no periods. Cause?

Hi I m 21 years old 4 11 and like 76pounds. I have lower abdominal pain on a daily bassis. My stomach looks swollen mid day to night but in the morning it s not. I get fevers and I vomit every so many days then I won t for a few days. I get this weird gurgling filling in my stomach sometimes you can see it move. I have not had my period yet this year. I m gaining weight. I m always hungry and thirsty no matter how much I eat or drink. I have asked doctors and I have taken pregnancy tests . Can you please help me? This has been going on for over 9 months