You have close contact with a known case of strep, now you have strep symptoms, and you're afraid to go go into a medical facility to get a quick swab to verify if you have strep. Yet you'd be fine just to pop some un-prescribed antibiotics bought from some kind of online 'kit' to hopefully cure whatever the illness might be?
I hope you've done it by now, but if not, go get your strep test. Untreated strep can have serious complications. If you're afraid of getting additional germs (or if you care about not spreading your germs to others including the medical staff), wear an N95 mask while there.