While a sore throat and fever can be symptoms of diphtheria, they are far more commonly caused by routine viral infections or strep throat. Diphtheria is very rare today due to widespread vaccination. A classic sign is a thick, gray coating at the back of the throat. If diphtheria is diagnosed, treatment requires hospitalization, a diphtheria antitoxin, and antibiotics like penicillin or erythromycin. Please do not panic. I recommend seeing a doctor who can examine your throat and perform a swab test to find the exact cause and prescribe the correct treatment.