Struggling with Overactive Brain and Anxiety

I will sometimes have to sit in my car action-less for an hour or so, just being overwhelmed by my overactive/discontent brain. While It is getting easier to pull myself out of the anxiety. it’s also still so hard, my thoughts will overthrow my ability to think rationally, and will make me analyze my every feeling (physical/emotional) with judgement, fear, worry, doubt etc. I know i’m going to continue to gain more control, but i have to close myself off and decompress in what can feel like such a dramatic way, just to regain my thought control- I don’t know how to practically apply that to a life that constantly demands my immediate attention and cognitive power..