You should seek the attention of a physician. What follows should not in any way substitute for professional medical care.
There are many causes of a sore throat, with streptococcus as one of them. Most are actually viral in etiology so there isn't much in the way of treatment. If you have been having runny nose, nasal congestion and a cough, then your sore throat is likely a viral syndrome. Drink lots of fluids.
In strep pharyngitis, your throat MAY be covered with purulent material. Of course, don't mistake mucus for this. If there is a lot of concern for strep, a rapid strep assay is available at your doctor's office. A throat culture (gotta grow the bacteria out on a media plate) requires an incubation time so the results will take several days. The consequences of strep throat can be devastating when the bacteria gets into your bloodstream and your body develops a response and attacks your heart valves. A quick course of penicillin or erythromycin will take care of your strep throat.
Sore throat may also be caused by gonorrhea (risky oral sex) or mononucleosis (epstein-barr virus).