22 days ago I had my first and only brief oral encounter with a man from India in a moment of experimentation. I met him online and he assured me was "absolutely" clean and healthy in every way. I have read mixed information online about what STD's I could have contracted and the likelihood of those infections occurring and it has caused me massive anxiety. I have also read that since this man, even though he was in his 40's, professional and married and assured me he was ABSOLUTELY clean, travels to the United States on business but lives in India where STD's like syphilis and hepatitis are far more common than they are here in the states. So, I am concerned about what I could have caught from this encounter. The details are, I went down on him for about five minutes, he didn't ejaculate in to my mouth, but while I was going down on him I did taste something salty which could have likely been his pre-ejaculate which I likely swallowed while I was going down on him. To my knowledge, and as far as I can remember there were no open sores or bumps on his penis. After finishing him with my hand, I showered and rinsed out my mouth with an anti-bacterial mouth wash.
Now 22 days later, after dealing with extreme anxiety, some depression, and the stomach problems to go along with them, I have lost about 8 pounds in 9 days. To be fair, my eating habits have been off and I have been dealing with irritations in my stomach since the event occurred. But I have also read online that HIV, Hepatitis and Syphilis can cause weight loss. I am seeing a doctor today about the anxiety and weight loss but I cannot get any conclusive tests for the STD's that I mentioned until about week 6 from what I read.
So my questions are,
1) what is my likelihood that I have contracted Hepatitis B from this one time oral encounter? Taking into account that this man is not from this country and is from what the internet considers a "developing" world.
2) Could Hepatitis B be causing weight loss this soon after an exposure? Especially, without a fever and the absence of other associated symptoms.
3) Could Hepatitis B from an oral encounter cause an irritable bowel and abdominal cramps?
3) Are there any reliable tests that I could take now that would tell me whether or not I have Hep B?
4) Since I was possibly exposed 22 days ago, I assume its too late to try and get the Hep B vaccine?
5) I've read online that Hep B transmission through oral sex is theoretical, have there been any documented cases of it ever happening?