Hi, welcome to healthcare magic, I am sorry that you are unwell
Bacterial tonsillarpharyngitis is usually associated with certain bacteria, though adults may be infected by bacteria that is different from what is commonly seen in children.
In addition, in some persons the bacteria present may be resistant to the antibiotic used.
In the presence of an intact immune system ( if you do not have any conditions such as diabetes
which is only one example or are using any medications likely to impair your immune system such as steroids
) then you will likely respond to your antibiotic regimen.
Your doctor may modify the antibiotics that you are using based on the swab results which would indicate which bacteria is involved and which medication it would most likely respond to.
I hope this information helps and I hope that you feel better soon