Common STDs would include gonorrhea, chlamydia, HIV, or syphillis. The Floxacin would cover the gonorrhea, but you may want to consider Doxycycline or Azythromycin to provide better coverage for the chlamydia.
A thorough prostate exam, including tests for prostatic secretions may be considered to fully evaluate for prostatitis - there are some cases that require an extended course of antibiotics.
If you continue to have symptoms, then imaging studies such as a transrectal ultrasound may be considered to evaluate for abscesses.
Followup with your personal physician is essential.
This answer is not intended as and does not substitute for medical advice - the information presented is for patient education only. Please see your personal physician for further evaluation of your individual case.
Thanks,
Kevin, M.D.