Test with a Duo at 28 days post exposure and move on.
Unprotected penetration is a risk, irrespective of the time of contact. Since you had a risk, the only way to rule out the possibility, is get yourself tested for HIV Duo, forth generation test, anytime 4 weeks after the exposure. It is true that risk was there but a single, isolated brief unprotected contact with some one of unknown health status is not that significant as you are thinking.
Having said that, get yourself tested after the specified period, collect your conclusive report and move on with your life normally. Words from the CSW alone do not relieve your from the test.
Next time, keep sex away from alcohol, they do not mix well