It has been going on for a while then!
It sounds like you probably should be seen by a doctor, unfortunately. Usually viral
illnesses should be getting better after about 5-7 days.
Your tongue may be dry/yellow because you are not getting enough fluids, so try to increase your intake.
I am suspicious that you may have a sinus infection or possibly strep throat. It could also be mono...it is hard to say without actually taking a look at you.
Strep or mono causes sore throat, swollen glands, fever. Mono causes significant fatigue
as well.....which you seem to be having.
If you have mono or strep, will often see white spots on throat but not always.
Sinus infections cause pressure, headache, fatigue, fever, sore throat, drainage.
I would keep doing what you are doing today but see a doctor tomorrow. Warm salt water gargles, throat lozenges, ibuprofen instead of aspirin (lasts longer).
If you have more questions, let me know.