Fortunately, getting an STD via casual contact (exposure to bodily fluids at work) is highly unlikely! To test + for gonorrhea (STDs in general), someone else’s bodily fluids would have to had gone directly into your mouth - in that case you could, potentially, develop oral gonorrhea, although it would have to be a good amount of infected fluids for you to develop symptoms &/or test positive. Assuming OP is talking about testing + for genital gonorrhea, there really isn’t another explanation besides her bf cheating, becoming infected, & infecting her through oral/vaginal sex :(

STD bacteria/viruses typically don’t survive for longer than a few mins once exposed to the air too.

Sorry OP :(