Hello dear! I have gone through your query and understand your concerns! I m sorry for the situation you are going through. Having a prolonged diarrhea for about a week, nausea and abdominal pain make me think about a gastrointestinal infection. In most of the cases it is a viral condition but it is healed after 2-3 days. It seems a bacterial infection has nested now, and has been complicated. Do you have fevers too, or blood in stools? If yes antibiotics would be the best choice and should be taken as soon as possible. I would recommend you ciprofloxacin which is a good antibiotic in gastrointestinal infections. Since you have lost to much liquids with your vomits and diarrhea, you should take ORS orally to replace them. Lactic ferments are necessary to diminish side effects of the antibiotic and arrange the bacterial flora in your intestine. Try to keep a light and watery diet. Please feel free to write again for further questions. I wish you a quick recover! Best regards! DR ERIOL.