Basically HIV is very difficult to get or to give we need a vigrous and long lasting sex which is not the case here. You had risk like falling from plane flying in sky. Remember always risk means risk and it does not mean you had got hiv so dont be anxious and dont go for test for such exposures as they are of meaningless risk.
No need for this new thread, since you were told to test at 28, not to test early which you have done.