Herpes sores appear typically within 2-20 days, and syphilis sores at 3 weeks, but syphilis is really uncommon in most developed countries, and you aren't at all at risk for HIV.
*You are only at risk for genital herpes type 1 from oral sex, if you don't already have oral herpes type 1. You can't get the same type again in a different location. You can have it without having symptoms - most never get symptoms.
I agree totally with grobick about the odds. We don't have actual transmission stats, and oral sex is a lot lower risk than intercourse is.
1. Yes, good news. Most cases of acute gonorrhea start before that. NGU symptoms, on the other hand, often start after a week post-exposure.
2. Odds are very low. It is very hard to assess risks in cold hard numbers. Does one in thousand really sounds scarier than one in ten thousand? Both seem pretty safe for me.
For HIV your risks are even lower.
3. You sure like numbers. Numbers may have magic powers, but they can't cure anxiety, while you totally have some anxiety issues.
4. Because the odds are too low. If you are worried, it is always a good idea to get tested.