You have nothing to fear yet,if you had unprotected sex with only one girl. Unprotected sex with multiple partner is a high risk factor. Incubation period for hiv is few months to 10yrs,when clinical manifestations begin to appear. Window period is about 2wks to 6months,when a person is hiv infected and starts producing hiv antibodies. During window period a person doesnot produce clinical manifestation and h.i.v test remains non reactive. In your case, you are almost crossing 6month, so wait and watch. Dont click your panic button yet. You must also take care of other predisposing risk factors of hiv. Blood for hiv after another 2wks may be done along with Blood for CD4+ COUNT, CD4+/CD8+ RATIO AND COMPLETE HEMOGRAM.