I can understand your concern.
First of all, tell me why would you require a antibiotic medicine for a viral fever? What good will it do in viral fever.?
Also tell me did you take those medicines only for one day?
Because if you had taken antipyretic today, you would have had relief in headache.
You need to complete a course of your medications once you start specially antibiotics.
And do not take antibiotics unnecessarily. This is how antibiotic resistance develops and then common antibiotics do not work any more and causes increase in the cost of treatment and you guys blame doctors.
Consult a general physician
Do not do self medication, its not your subject and you do not know.