Open mouth kiss does not put you at any risk of HIV, even if your gums were bleeding because saliva does not carry the virus. Even if there was a small amount of blood in the mouth and it was infected, enzymes present in the saliva were capable of inactivating it instantly. With this Zero risk activity, PEP was absolutely unnecessary and I doubt if a qualified doctor prescribed it for you.
Your symptoms are not at all related to HIV, it is your stress and anxiety. Sore throat and cold could be picked up from anyone around us, not necessarily from the guy you mentioned.
HIV symptoms do not appear before 1-2 weeks after the exposure, so these symptoms have nothing to do with HIV.
In a real risk situation (Unprotected anal / vaginal sex with someone of unknown health status), PEP is effective if started within 72 hours of the exposure.