The good thing is that infants are born with some natural immunities from there mother, which help to protect them. It is not necessary to leave the residence, however, I recommend that you wear a mask at this time if you hold or are near the baby, to prevent passing any airborne germs. It is most possible that you don't have strep, but I am glad that you are being cautious. Wash your hands well, before holding the baby and wear a mask. Be aware if you have a sore throat or a cough, because then you can have a throat culture taken to be sure.
Good luck and enjoy the little one!