What Causes Headache With Painful And Swollen Throat?

i have had a really painful throat for 3 weeks it looks swollen inside. i can not eat and barely drink. my digital themometer says my temperature is 41.3 degrees. i have a runny nose. i dont feel stable on my feet. i can barely do anything. i have had a constant headache. it does not feel like a normal cold .i have tried all the flu treatment out the pharmacy and nothing is working