Nicely put monkeyflower.
Your risk factor for C. dificile was not your trip to the massage parlor but your antibiotics. The antibiotics kill off normal bacteria which are present most people’s colons, allowing the C. dificile bacteria which are also present in many people's colon but resistant to antibiotics to overgrow and cause severe diarrhea and abdominal pain. I know of no information to suggest that C. dificile is more common in person with HIV than person who do not ahve it.
Monkeyflower is also correct that C. dificile is highly contagious with the most common route of spread being due to poor hand washing. Take care. EWH
Not a doctor, but I thought I might be able to reassure you a little while you wait, sleeplessly, for one of the good doctors to respond :-) I think your c diff was probably caused by your 14 day antibiotic use. That's the usual cause. Antibiotics can kill off some of the 'good' bacteria in your gut, allowing 'bad' bacteria like c diff to overgrow and thrive. Further reassurance: you weren't at any risk of HIV from what you describe.
Of course, I don't know that knowing it's not related to HIV is actually all that reassuring; c diff does not sound like fun. I hope you feel better soon.
On a side note, I'm not medical, but I work in an ED. There are lots of ooky bacteria and viruses out there. Wash your hands.