Thank you for your response. I will get tested at the intervals you mentioned and work on getting past this.
It seems you are reacting mostly to the guilt you feel from your sexual indiscretion. While nobody can say there was no STD risk, he risk of HIV definitely was zero or close to it; HIV remains rare in the large majority of heterosexual men and women in the US and other industrialized countries. The chance of other STDs is higher, but still quite low in this circumstance. The symptoms you describe do not suggest any STD; if you caught anything from your weekend partner, it was a cold, nothing more. To the specific questions:
1) Statistically, probably the highest risk was for chlamydia, with much lower risks of gonorrhea and syphilis. Tests for gonorrhea and chlamydia are accurate within a few days, so you could be tested at any time. Syphilis is extraordinarily unlikely, but if you want to be tested, have a blood test about 6 weeks after the exposure. The same time frame works for HIV testing. HPV was a potential risk, but there is no accurate test to detect new infection, and in any case HPV should be looked at as a normal consequence of being sexually active. All women should have periodic pap smears to check for early HPV-related disease, and your affair doesn't change that advice one way or the other. HSV is an unlikely possibility, especially if you don't develop symptoms of herpes; I don't recommend testing. Finally, a general gyn exam -- perhaps around the time of an HIV and syphilis test -- could assure you didn't pick up trichomonas or bacterial vaginosis.
2) You only need the tests and intervals suggested above. But do not test yourself by going anonymously to a laboratory or online. See a knowledgeable health care provider and folllow his or her advice.
3) See above.
The main thing now is not to panic. The chance you caught anything (other than a cold) is very low.
I hope this helps. Best wishes-- HHH, MD