Yes. You got the right diagnosis. Many of the people most of the time get viral infection. So it is customary to regard these as viral infections. If it is viral infection then antibiotic does not help and if given when not indicated can increase the chance of emergence of resistant strains of micro-organisms. But clinically there is no way of differentiating between viral and bacterial throat infections. If symptoms are severe or are progressing (can be due to secondary bacterial invasion) then it may be considered as bacterial. Blood test
(CBC) might give some clue to differentiate.
So continue with treatment given.
If your symptoms increase then antibiotic Co-amoxyclave for 5 days can be taken.
Wish you good health