Unreasonable coughing. Please suggest.

- Cough Started last week, without any cold or runny nose etc but after some headache in evening. - only on one day fever was above 100, rest evenings about 99.6 - took cheston cold for 3 days, then switched to Cephadroxyl tabs (morning evening) antibiotic for 8 tabs in total. - it is neither increasing too much, no phlegm ( quite less light green and not thick) and neither going away. - one doctor prescribed anti allergy tab for next 2 weeks and syrup grilinctus as she said antibiotic is not acting on viral and could be due to allergy. - but not much improvement. Cough remains in day as well as little more at night, like an irritant in some lower end of air pipe but nothing comes out.moy able to sleep and rest due to this. Please suggest.