I'm a fellow OCD sufferer and know exactly what you mean. I'll share with you how someone explained it to me that made everything much clearer and might bring you some insight, even if it sounds a bit obvious. What a lot of people think about OCD (probably due to how it's portrayed in media), is that the person doing a certain action (checking something, counting something, etc.) is doing it because they have some positive association with that action. But it's actually the opposite: the behavior (the compulsion) is meant to soothe/help you *avoid* the bad feeling you get from not doing it. That's why OCD is often called an anxiety disorder.
Let's break it down, using an example from my own life: you have an obsessive thought that gives you anxiety (e.g. my mom will die), and an association with a behavior (e.g. saying "I love you" at the end of every conversation with her). I feel *compelled* to say I love you to alleviate the anxiety of the obsessive thought. The result is "magical thinking," where we tie an unrelated action in our heads to avoiding a bad outcome.
This may already be obvious to you, but I think that the kinds of thoughts you're describing function the same way. They are sometimes called intrusive thoughts, and are another kind of obsession. They feel terrible to have, so you take an action that soothes you and makes the intrusive thought go away. In your case, being hyper-aware probably alleviates your anxiety about getting hit. Or at least, not being hyper-aware would make it unbearable.
All this to say that what you're experiencing not only really resonates with me, but is a great example of a very common OCD thought pattern. My symptoms were much more severe in my teens (I'm in my twenties now), and I found success with what's sometimes called exposure therapy. Under ideal circumstances, one of the best ways to combat these magical thoughts is to do the thing that causes anxiety without doing the compulsion (to use another personal example, getting something sticky on my hands and not immediately washing it off). The idea is that eventually, your brain learns that the thing you are anxious about is not going to result in catastrophe, and you lose the need to do the compulsive behavior.