First try to confirm the HIV
status of your contact. If your contact is positive for HIV then only you may need a test. Usually Antibodies to HIV start to appear from 3rd week but may take upto 3 months. You are saying it has been 6 months since the act and if you have acquired the disease, your antibody test would have been positive by now.
So you need not to worry and consult a physician for your throat complaint but I request you to repeat the antibody test at 12th month as there will always be exceptions. Contact if you still need further assistance.