Tonsillitis appeared on day 3 of flu, still painful & it's day 5 (worst it's been), is another 5 days underestimating the length of its infection? other flu symptoms have eased, only chesty catarrh cough persists & right side throat lymph node pain?

We don't normally prescribe antibiotics for uncomplicated influenza,a viral infection. However, tonsillitis may be caused by a coexisting strep infection. I think a rapid throat culture should be taken and if positive for strep, appropriate antibiotic treatment will be needed. Also,while you're at it, I advise a monotest& a cbc and diff in case you're negative for.strep