you are having positive test for UTI (means Urinari Tract Infection), in which chills
are possible along with body aches muscle pains etc. for this you have taken medicines only for 5 days, which is not sufficient for UTI purpose, for this at least you are advised to take proper medicines after culture & sensitivity test of your urine for about 10- 15 days period and to have good flow of urine you must advised to take plenty of liquids along with citrus liquids and alkaline liquids to protect from burning micturition.
If you still feel chills & rigors after above treatment than you must go for check up for malarial fever
or complete CBC examination and get the treatment accordingly.Hope you will get relief by this suggetions. good luck, take care