Dark Night of the Soul is just a conceptual Christian term for ego-death, and every seeker who goes through it experiences ego-death differently.

Some will pass through the full dissolution and letting go of the illusory ego-identity with minimal “darkness” or disturbance. They are the ‘light’ ones, the ones who were already carrying their sense of a ‘personal ego’ very lightly, not believing it was ever anything real & substantial.

Some will feel such a deep yearning for ‘God’ or The Reality, yet simultaneously be very attached to their sense of “me,” this seemingly-real separate self, and it will kill “them,’ literally, to let go of that. They will feel exactly as one feels when they are physically dying, clinging desperately and experiencing maximum fear and agony.

And every degree in between these two.

The individuality of the ego-death experience extends to the length of time it lasts, also. Some will feel like they went from believing they had an ego to realizing it was always a phantom in an instant, or a few short weeks. Others will wrestle with their dissolving seemingly-real ego for many months and even years, before finally breaking through or dying, whichever comes first.

So ‘several months,’ or longer, as suggested by the questioner, is not at all uncommon. The questioner also asked for the answerer to recount ‘what was it like,’ but since it’s such an individual experience, I don’t see too much value in that. Suffice it to say that mine was in the long & brutal category, terrible physical and mental anguish that seemed like it was going to be lifelong. But that’s probably just because my ‘seeming’ ego was ‘seemingly’ the size of one of the giant gas planets. Call me Jupiter, the Gas Ego :-) Or call me Teja. It doesn’t matter. All that’s gone now :-)