A one time, unprotected vaginal sex exposure is very LOW risk. The statistic is less than 1 percent of transmission. I would not suspect you got HIV but do test at 28 days or beyond with a 4th generation DUO test.
Each situation is different, so statistics aren't guaranteed to work for everyone - especially if the other person is negative. Having unprotected vaginal with a sw is not a good game plan though.
The shorter the time of exposure makes less risk than a longer time. If you are concerned, then take a duo test after a month or any other test after 3. Avoid checking for symptoms, because they can't prove ANYTHING, and constant checking will make you more worried. Good luck with your decision.