HIV is out of the question. You should forget about it. Hep B is out of the question as well (it is very rarely transmitted when you are exposed to saliva only).
Your syphilis tests results are also very conclusive and you had no symptoms, so, no worries.
But those are other STIs out there.
You never tested for chlamydia or gonorrhea. Since you had no urethral symptoms, those are quite unlikely.
You also had a low risk for HSV and HPV exposure, but there are no reliable tests for those.
Addressing to your question, I feel it is more of a guilt problem. It is better to seek professional help, if you feel your guilt is too heavy of a burdeb.
Your risks for STIs were assessed above, they are slim to none.