You were at virtually zero risk for any STD from the exposures you describe, and the symptoms you describe are not those of any STD.
1) Of course STDs occur without symptoms. But this question doesn't otherwise make sense; it cannot "lead to infecton" if an infection is already present. Perhaps you mean "lead to complications"? Yes, asymptomatic STDs can lead to complications. But there is absolutely nothing in your story that suggests any risk for that.
2) Your symptoms are not those of herpes, period.
3) Although I am confident about what is NOT causing your symptoms (no STD), I won't speculate as to what IS causing the. That's the job of your primary care provider.
4) In my experience, when a person suspects his or her own symptoms are due to anxiety, stress, guilt etc, s/he almost always is right. So definitely yes, you should "calk this all up to the feeling of guilt". And by all means stop looking at the internet for STD symptoms.
Good luck-- HHH, MD
I will just comment on your #4 and let the Dr handle the rest ... I know for a fact that our minds are very powerful and when you add some guilt and anxiety in that mixture your body will exhibit whatever symptoms we think of. I have had every std in the book in my head however have been negative for all. Reading forums like this can be good for educational purposes and other things but for people who are prone to anxiety issues it causes us some unnecessary stress. When your reading about someone else itching/tingling and trying to figure out what is wrong with you i almost guarantee you will start itching/tingling and questioning everything you have ever done then in your head you have what the person whose story you are reading has. Good Luck to you