It sounds like you received oral sex, and didn't give it?
Oral sex is never a risk for HIV, and if it were, you wore a condom, so you're protected. You're also protected against gonorrhea, NGU, and chlamydia (which is rarely a risk from oral sex).
The thrush is a coincidence, unless you performed oral sex on the CSW or kissed them. If that happened, you could get thrush. Thrush happens for a lot of reasons - medications, excessive mouthwash use, diabetes, etc., are all common causes of this. Yeast is naturally in our bodies, and sometimes it just overgrows. If you were diagnosed with this 2 days after this encounter, it's not from that. It would take longer to become thrush than 2 days.
I'd say it's coincidence.