As someone who is quite anxious myself, I am certain that you haven‘t injured yourself. Without an impact, you cannot have the trauma in traumatic brain injury.

I often fall victim to the fatalistic images that my brain conjures up, they are very lifelike and to be honest to some extend it is just the mode of being that is most familiar to my everyday experience.

For example on Sunday I took an (american) football, that was deflected, to the temple. I would never play an actual game involving tackling, but I was throwing with my brother and I tried to catch the ball awkwardly, so that it came down and struck my temple. I startled by the impact, but I was not aware of any immediate symptoms , so my first thought was how lucky I was. A direct hit with a football hurts, a indirekt one you still feel the weight of the ball). When trying to search my glasses immediately afterwards I felt off, on Monday I could not concentrate on simple tasks and Tuesday and Wednesday I felt feverish.

I am honestly unsure whether I could have injured myself, but I was very sure that the most important thing for me was to avoid stress either way. Of course I still replayed the incident in my mind a thousand times (heck, I am obsessing over it right now), but I am proud that it didn’t make me question my whole life all over again.

As an anxious person, it sometimes almost feels like it’s a responsibility towards myself and others to be worried. So I can make the right decisions and do the right thing. But concerning my brain health, I am learning slowly that exactly the contrary is my responsibility towards myself: not to constantly agonize over it.

I also struggle with over analyzing any bumps or jolts I sustain. I've replayed this most recent jolt over and over in my head about 50 times at this point. I agree that regardless of severity its important to avoid stress. If anyone had tips on down regulating the anxiety response from such incidents I'd be very interested.

Meditation would help. Finding a place where you can calm the mind. All meditation is not the same and there are many ways of doing it.

Explore the sticky threads at top of the page-
here is one that might be helpful.
Anxiety, bumps, symptoms , treatment info links