I had unprotected vaginal sex with a female the next morning noticed a sore on my penis frenulum that also was leaking then felt flu symptoms ?

STD is possible...: ...for any new genital sore and very likely for urethral discharge (if that's what you mean by "leaking"). But no STD can cause symptoms so soon after exposure; if an STD is the cause (herpes, syphilis, gonorrhea, chlamydia, nongonococcal urethritis), you had it before this exposure. However, you exposed her, so you both need to be examined and tested ASAP, as do any other recent sex partners.