Krishna speaks8.18

अव्यक्ताद्व्यक्तयः सर्वाः प्रभवन्त्यहरागमे।रात्र्यागमे प्रलीयन्ते तत्रैवाव्यक्तसंज्ञके॥

avyaktād vyaktayaḥ sarvāḥ prabhavantyahar-āgamerātryāgame pralīyante tatraivāvyakta-sanjñake

Word by word
avyaktāt — from the unmanifestedvyaktayaḥ — the manifestedsarvāḥ — allprabhavanti — emanateahaḥ-āgame — at the advent of Brahma’s dayrātri-āgame — at the fall of Brahma’s nightpralīyante — they dissolvetatra — into thateva — certainlyavyakta-sanjñake — in that which is called the unmanifest

The verse says

At the coming of day, all manifest things appear out of the unmanifest. At the coming of night they dissolve back into that same unmanifest.

In plain words

Appearing and dissolving, described as a rhythm.

Not a catastrophe, not a punishment, not anything going wrong.

In, and out, the way breath works.

Where you've felt this · in health

You go to sleep, and for a few hours there is no you and no world either. You do not experience that as a loss, because there is nobody there to be at a loss. In the morning it all comes back in order — the room, your name, your age, and what you were worried about yesterday.

Going deeper

Dissolution is not destruction, and the whole comfort of this passage depends on the difference.

Avyakta means unmanifest: not gone, not destroyed, simply not currently appearing. Things go back into it the way a wave goes back into water, and the water is not diminished by the wave ending.

Every night you do a small version of this and it frightens nobody. Consciousness withdraws, the world stops being presented, and you return in the morning without having been rebuilt from parts.

What this offers is a way of thinking about endings that is neither denial nor dread. Something not appearing is a different fact from something not existing, and almost all of our fear about the first is borrowed from the second.