Dear patient, I read very carefully your question, and here its is what I think of your situation. First I will go on explaining it and then I ll write my recommendations. The chronic vomiting and diarrhea seems to be like symptoms of kidney stones who are causing a kidney infection. Also, being persistent for a long time they have taken you to a dehydration point which is upsetting the kidney much more, causing you the severe flank pain. Your kidney is calling for help. The persistent diarrhea and vomiting also have taken you to the point where you lost a lot of weight, and that makes sense because you are losing many electorolytes, proteins etc. Your body is starving although you may not feel hungry. The horrible night sweat and fever go with the diagnose of kidney infection which need urgently to be treated. Suggestions I may write down many form of treatments and medicine, but that will not help without this first steps: 1. urine analysis lab count. 2. urine culture 3. blood analysis and culture 4. copro culture 5. total abdominal ultrasonography echo (especially kidney). These are needed to confirm the diagnose and decide for the right antibiotic that most probable you need to take. Mean while, drink a lot of water, juices, eat fruits and other foods that contain fiber. Take loperamid and reglan for diarrhea and vomiting. Include serum (intravenously hydration), and paracetamol, or doses of steroids for the flank pain. Hope this helped. All the best, Dr. Eni