Hi welcome to Health care magic forum.
Thanks for asking a question to H.C.M.Forum.
You had Influenza
B and got treated , then had stomach pain, then you had flu like symptoms and getting treatment, no full relief, symptoms are unbearable.
It appears that there is secondary infection of the throat with bacteria. I advise you to consult your doctor again, for follow up.
If no relief you have to get the culture and sensitivity of throat swab , besides other routine tests for confirmation.
Wishing for a quick and complete recovery.