Hello clandestine: I'm sorry you are having such a difficult time with this. I'm an older person now. And I've never had a specific traumatic brain injury. But ever since I was a very young child, my head has taken a beating. (I'll spare you the details.) I was in one serious car accident.

I've never had actual panic attacks, as I understand them. But what I have experienced is that, whenever I've been out in public, I just become progressively more stressed until I finally get back home. It's not as bad now as it used to be. But there was a time when I would become so anxious I'd become dizzy & disoriented. I never did anything about it in terms of seeking treatment though. And, over the years, it has gotten better. At this point in my life though, I live a pretty solitary lifestyle.

One thing I do, however, is I walk our dog around the neighborhood every day. I couldn't count the number of close encounters I've had with cars when I'm trying to cross the street. Drivers just don't pay any attention. And they just don't seem to care. Sometimes they even cuss me out as they whiz past me! I also become very angry! And I've been known to cuss them out as well. And the whole experience makes me depressed & anxious as well. So I know what you're talking about here.

I don't know if I really have anything I can offer in the way of a remedy. From my perspective, the way you (& I) react to situations we encounter on the street is just one example of more "overriding" anxiety conditions. I don't know about you, obviously. But in my case, anxiety is something I have struggled with pretty-much 24 / 7 for many years. The anxiety I experience when I'm out on the street is just one particular circumstance. So, at least in my case, what I try to do is to "attack" my anxiety condition in general rather than to focus on the particular anxiety I experience when I'm out walking our pooch. And the way I do this is primarily through the practice of meditation & yoga. More specifically, I practice mindfulness yoga & primarily walking meditation. I do a bit of sitting meditation too. But I find doing yoga mindfully & doing walking meditation is much more efficacious for me than sitting. (By the way, I'm not on any med's nor do I see a therapist. I've never done CBT either.)

I do believe you make an important point when you write that you know the techniques you're supposed to use when you're in a panic-inducing situation but but you can't seem to implement them when the heat is on, so to speak. I'm a follower of the Buddhist nun Pema Chödrön. And in Ani Pema's writings, one of the points she makes is that we have to learn how to handle the little emotions & feelings we encounter every day so that, when we are faced with a really difficult situation, we do what we need to do instinctively. If, in one of those more challenging situations, we have to stop & think about what it is we need to do, then it's too late.

There is one technique for dealing with difficult emotions & feelings (& also with intrusive thoughts which I have a lot of) I use extensively & am very fond of. It is a Buddhist practice called compassionate abiding. One does not have to be a Buddhist to practice it though. Here's a link to a mental-health-oriented description of the practice:

Relieve Distress By Allowing It: Compassionate Abiding 11 | Mindset: Perspective Is Everything

May it be of benefit.