I think in my case, although "panic attack" is the generic description I use, it would probably be more accurate to call it an "existential crisis". It is probably easier for people to relate to "panic attack" than it is to relate to "existential crisis", which is why I use the prior term rather than the later.

An existential crisis, in my experience, is that point we get to in human comprehension, where all ability to understand breaks down. The human mind is limited in its ability to comprehend, as everything that it perceives is a form of conceptualisation. Conceptualisations in themselves are apparitions, not being anything in reality except an idea formulated in the mind in response to stimuli.

When all content is lost, when there are no longer any forms emerging into consciousness, when we stand at the threshold of the mind, the event horizon of conceptual reality, when we stare into oblivion, ready to be annihilated.

This my friends, is why I panic.