What you experienced was the gut-brain axis failing under extreme metabolic stress in real time. 3-4x caloric demand and your enteric nervous system was under enormous strain dysregulation of serotonin production, inflammatory signaling flooding the vagus nerve upward into brainstem arousal states, directly degrading the prefrontal predictions that normally keep your self model coherent and future oriented. the nihilism wasn’t a psychological response to difficulty it was your predictive hierarchy collapsing from the bottom up, the higher level model of who you are and why this matters losing the competition against overwhelming lower level distress signals. The fact that it resolved when the intestinal distress subsided is actually clear indicator that mood and cognition are downstream of gut state more than we like to admit. our gut makes a like 80% of our serotonin or something