HIV positive results don't show up for 3 months, unless you live in an area that performs the RNA testing, which shows in 9-11 days. There is the possibility of a false positive or a false negative. You must not stress yourself out on this - there is nothing you can do until test results come back. You can, however, do the following:
Tell your manager and place a written description of the event in your HR file. Make them sign & date it.
File a Police Report & provide them a copy of the written event description.
Check out Victims Services in your state - they may pay for the test(s) and possibly counseling.
I wish you luck, and hope everything turns out OK.