Strep throat getting worse after 2 type of abx. initially started to improve, but by day 4 started getting worse - pus on throat & infected lymph node?

Not good: Some people do not absorb oral antibiotics very well. You may need to get some shots of antibiotic, IV doses. May also need to make sure you don't have mono at your age. This can cause false positives with some strep tests and would not get better with antibiotics. Especially with "pus" and "infected lymph node" this is a consideration.

Throat: Make sure to get a culture and sensitivity..... The antibiotic might be resistant to the strain of bacteria

You could have mono: which would not respond to antibiotics. Some people can have. both. Call your doctor and see if they will order a monospot test.