Hello and hope you are doing well.
The symptoms described could be due to an infection, most probably streptococcal or a viral infection. It has started as a cold and progressed to a throat infection.
Strep sore throat needs to be treated with an antibiotic as strep is a bacteria. Viral sore throat is best treated with rest, warm oral fluids and (OTC) tylenol (acetaminophen) or ibuprofen for pain. If you develop a fever, or if there is enlargement of the tonsils with pain or if there is white coating on the tonsils, you will need to consult your primary care physician for a strep test, which if positive you will be given antibiotics.
In the meantime take OTC multivitamins. Take plenty of warm oral fluids and lots & lots of rest. For further relief from your symptoms you could do warm salt water gargles and stream inhalations. Please ensure to do this prior to your meals.
Hope this helped and do keep us posted.
Talk to your pharmacist about what is safe to take.
Never take anything without asking them about drug interactions.
Have you tried using a nasal flush? I find they really help.
Prop yourself up when you sleep with many pillows and use a humidifier by the bed.
Ask your pharmacist about taking oregano oil. It's a natural antibiotic.