I agree very much. I have had only two panic attacks in my life (I think they were panic attacks) and one of them was about kind of existential questions like this. The root of that problem of mine at that time was that I was building too many theories to explain or describe the world to myself. Like if I could only have my own reliable description of the world it would mean I was safe, or I was always right, which meant I couldn't be threatened anymore. I don't even remember exactly the thoughts themselves, but I think everything was in that spirit. And the problem is that these concepts have problems of their own. Like, it's a stupid example but the sentence "this sentence is incorrect" raises a paradox. But such paradox can't exist in nature, paradoxes can only exist in our own minds because they are inherent to concepts, which will always be very imperfect ways to describe reality. Yet, I was trying to find kind of the perfect concepts or perfect philosophical principles that would be above everything (kind of), it felt like I was building a solid building of theories, but I was just building my own mind jail. Now I think there is no way I can state a philosophical principle without it contradicting itself at some point. I thought I was building a kind of vision of the world for myself that was more right, or more solid, but at some point I realized it was all too rigid, and just like rigid buildings don't survive earthquakes, it collapsed under the weight of its contradictions and this is what triggered a panic attack for me. I was living in the reality of my building of concepts, and when it collapsed it really felt like reality was collapsing, and I was just facing impossibilities and contradictions without being able to make anything out of them. I went from full control to zero control. And even after that collapsing, it was tempting to make another theory out of it and try to explain it again and start building again... that's what I do. But confusing reality with concepts ultimately makes us live in many contradictions that can't hold if we really look at them.