Hi I had sex with prostitute about 3 weeks back and i used condom she give me oral for about 30 sec which was unprotected ..since few days I am feeling burning while urinating and lil pain in my testicles when I masturbate .. I went to the doctor he did urine test and its Negative for any infection... Still he gave me doxycycline dosages 100 mg 2 times a day but still no relief after 3 days ... please advise if I have std