Thank you Nick, I feel a little better. I plan to test again this weekend which will be 7.5 weeks.
Military testing is for sure done, This may help ease your mind, but you still put yourself at risk (Low) but a risk is a risk. You will need to test 3 months after you were exposed. You may also test at 6 weeks for a very good indacation of your status. A 18 day test is not good enough.
I am sure you did not get HIV from this exposure, but the only true way to be sure and stop worring is to test as detailed above.