Thanks for your query.
When a person gets infected with HIV, usually it takes 6 weeks to 3 months for seroconversion
(time when the antibodies
to HIV form in the body) to occur. During this stage of seroconversion the person may have fever, sore throat
, rash, headache, diarrhea and other flu like symptoms. You had sore throat just after 4 days of having unprotected sex which is too short for a seroconversion to occur. Probably it is due to an upper respiratory tract
infection. If you want to confirm you can get a P 24 antigen levels in your blood. Discharge and swollen lymph node in your groin may be due to some infection (might be due to some other sexually transmitted disease
apart from HIV).
It is not safe to have unprotected sex with unknown person. In future please take necessary precautions.
I suggest you should consult your doctor immediately to get a work up for your problem.