you had a sex with prostitute without protection. that is your mistake, but if your sexual partner is not having any sexual transmitted disease or HIV then you shouldnt be worried. but i advise u to go for HIV testing and other investigations for sexually transmitted diseases. u can also approach the same woman and inquire about her viral status and other diseases and whether she has gone through any investigations recently or not, u can just ask her about your concern she will give u a better answer...