Ask anything you want, but if this is all you think about I would suggest therapy to help you deal with this.
Vance,
This is all I think about. I have a couple of more questions. Can I ask them or back off?
Yes there would be anti-bodies if you had syphilis at any point.
Zithromax probably didn't do anything if you had syphilis. So you can be pretty confident that you never had syphilis.