Around June 22nd of this year i had unprotected intercouse, with someone of unknown status. I took my first hiv test 1 month after-negative..a PCR at 2 months which was also negative..two more elisa tests at 3 and 5 months both negative..however i feel i have symptoms being tired all the time...constant back and head aches..was wondering if a negative test at 5 months should be conclusive..im going to go again in a month...6 month mark..also is there a possibility that i could be HIV Positive..and test negative at 6 months? Thank you for you time.