Well, if you think about any circumstance, there is always a remote possibility. That's why doctors and scientists will never say something is 100% because their is always some freak occurrence of something happening that no one thought possible. You can't get hung up on that though. In the case of drinking blood, yes there is a very, very small possibility that a human doing so could be infected with HIV. The important thing to remember is that there is a difference between possibility and PROBABILITY.
Is there a possibility that I might be attacked by a shark the next time I am swimming in the ocean? Yes, humans do occasionally get bitten by sharks. Is it probable? NO. Am I going to never swim in the ocean again because there is a tiny possibility? NO.
In your case, a chain of IMPROBABLE events would ALL have to take place in order for you to be facing any real danger. Your OCD is stuck on the word "possibility" and making you feel that just because something is remotely possible, it's also probable. It's not.
I think that one of the things at the heart of OCD is that people who suffer from it have a low tolerance for the uncertain. They want to be 100% sure that something is one way or another. Even a tiny chance that something might go wrong sticks in their heads and they can't let it go. Most people hear the facts, decide that it's really nothing to worry about and go on with their lives. They realize that certain things are possible, but they just decide to deal with it if it happens and to not think much about it in the meantime.
Life is full of risks and the unknown. Treat your OCD and you will become more tolerant of risks and thoughts that cause anxiety. They will never completely go away, but they will become tolerable and will not take up as much of your time and enjoyment of life.
Hi there. I saw that JGF25 gave you some good advice about OCD in general, and I agree with her 100%, but I thought I might try to settle you down a bit. The first thing I want you to do is breathe. Breathe slowly in through your left nostril and back out through your right nostril. In through the left side of your nose, out through the right. Really concentrate on the sensation of the air entering and exiting your body for about 5-10 minutes.
Ok, do you feel a little calmer? You should - that was just a little meditation exercise. Do it several times a day and you will start to feel less anxious in general. About your fears:
1. I can't think of a single explanation as to how blood would get into a cup with ice in it. Seriously, how would that happen? No one drinks blood and if someone was bleeding, they would grab a napkin or towel to try to stop the bleeding, not let it drain into a cup. I used to bartend and I can think of several drinks that might look like blood but are just cocktails. The brownish substance on the cup could have been food or lipstick - brownish shades are in fashion this year.
Even if by some freakish chance there was blood in the cup (I still don't see any way how it could be), you don't know that it had HIV in it (less than 1% of the population in the US is HIV positive). And even if it was HIV positive blood, drinking it would probably not infect you. Saliva breaks down anything it encounters (part of the digestive process) and it also contains proteins that greatly speed up healing of any breaks of the skin inside the mouth. Once the "blood" hits your stomach, the acid in your stomach would finish off any HIV that was left. On top of all that, HIV does not survive long outside the body - some estimates are just minutes. Drinking blood simply is not a viable way of becoming infected with HIV.
2. You cannot get HIV from getting someone's spit in your eye. It simply does not happen. Saliva from a HIV-positive person does contain trace amounts of the virus but nowhere near enough to cause an infection (the same goes for tears or sweat). Again, you have no idea that the person is HIV positive (very few people are) and even it we give you the benefit of the doubt and assume that they were positive, it does not matter. You cannot become infected from a drop of saliva getting in your eye. No way, no how.
Hopefully you feel a bit better after reading this, but you really need some help to get your OCD under control. If you lose your fear of HIV infection, chances are your OCD will just start you worrying about something else.
I know right now what you are going through *****, but hang in there, you are going to be fine.