Hi welcome to the health care magic You are mostly having viral gastroenteritis as per history Your fainting and muscle ache is because of dehydration and loss of electrolyte in diarrhea So maintain hydration with lots of water and take ORS also to replenish lost electrolyte Stool examination should be done to exclude pus cells, bacteria and parasites eggs... If any of above present than treatment differ according to cause and antibiotic or anthelmetic drug started accordingly If needed USG done for further work up If non infective diarrhea than antisecterotory racecadotril like drug can be prescribed Consult physician for examination and further treatment plan according to your physical condition Take care