I agree, there truly is a zero chance of contracting HIV from that situation. I have severe health anxiety and OCD as well so I know how overwhelming a fear of an illness can be. Please try not to let this worry take over. I would do what cj29 suggests and try and seek some therapy or talk to your doctor to help alleviate your fears.
Good Luck
Are you getting treated for your OCD? OCD and health anxiety can go hand in hand in my opinion. There is zero change that you could have even remotely gotten it from what you describe, but that doesn't subdue our fears when we worry constantly about it, in my experience. Do you have access to therapy? For me, confronting the issues head on gives you the tools to effectively deal with your fear quite rationally...keep us posted!