refers to the San Francisco city STD clinic, you are at one of the most expert sites there is; and in general, most San Francisco HIV
clinical services are highly reliable.
Despite the obvious high risk situation, the odds remain strongly in your favor. The large majority of unsafe exposures, even among gay men with anonymous partners, and despite gonorrhea or other STDs, do not result in HIV transmission. So follow the clinic's advice, and stay mellow as you await hte test results.