had unprotected sex in april 15th and few times in may with the same girl, had been tested negative on june18th, had another test on july 28th , was negative, i know it is supposed to be 3 months after the last exposure, the girl i had sex with, haven`t had sex with anybody else except me since april 15th, ...so , my second negative result was after 3 months from first exposure...what do you guys think about this?...thank you