Hi welcome to the health care magic In fever, with less drinking water dehydration can occur and so less urine can be there... Here I will advise you to get your physical examination and following work up for detecting cause for fever ..... -Auscultation -CBC -IGM dengue if suspected -Peripheral smear examination for malaria -liver enzymes study if yellow sclera present -ESR etc.. If CBC shows high eosinophila than Allegra like antiallergic drug prescribed If neutrophilia than antibiotic needed Meanwhile with decongestant Symptomatic management done Take care Consult physician for examination Hope this will help you