No condoms were used because you didn't really need one. A 2 minute blow and a couple second hand job carry no risk of transmitting anything including hiv. Your symptoms are totally unrelated to this encounter.
Sorry, I misread the condom comments. But it doesn't change anything in my response.
HHH, MD
There was no condom use. Sorry about that being unclear.
1,2) No STD regularly causes "flu-like" symptoms except HIV. That's the "exhaustive list", period.
3) Since a condom was used, there was zero risk of any STD.
Your symptoms cannot be due to any infection acquried during the sexual encounter you describe. No STD and no viral infection--including influenza or the common cold--can cause symptoms the next day. All those require at least 2 days before onset of symptoms.
On the other hand, the symptoms you describe are not "flu-like" anyway. If they are related to the sexual event, it is purely the result of an emotional/anxiety reaction to that event, nothing more.
Good luck-- HHH, MD