I relate to the "Constant mini-panic attack" idea very very much.
I call it "cognitive panic" (just my own term, so don't use it with a doctor or they'll think you're nuts, lol). In a "regular" panic attack, the body generates excess adrenaline and heart races, chest tightens, etc.
But I stayed in a kind of CALM panic state - I looked normal on the outside and my heart wasn't racing, but inside my MIND the thoughts were going 90 miles an hour and I felt like I seconds away from losing total control.
It's really NOT panic, but a form of annhiliation anxiety that stems from a (false) belief that we must HOLD ON to our own mental state, to watch it, to self-observe, in order to keep something horrible from happening. It's as if the mind is clenched tight like a fist and we're afraid to let it go, to relax it for an instant because it feels like that is when we'd go totally insane.