In Buddhism, they describe a few phases or facets of the dark night, meaning the phase that comes after arising & passing away and before equanimity.
Dissilusion. Clarity, mindfulness and focus drops away. It becomes difficult to practice, at least in the same way (clear, stable, focused) as before.
Fear. Anxiety and fear.
Misery. Sadness and loss.
Disgust. Suffering and unpleasant sensations.
Desire for deliverance. A desire for the misery to end.
Re-observation. A cycling of the previous five stages.
The recommended “solution” to this is inquiry, and feeling the sensations as sensations.
Read more about these stages, and some good practical advice, in Mastering the Core Teachings of the Buddha by Daniel Ingram. He writes from a naming practice context, so although the specifics of his advice often applies more to that practice, much of it is helpful for anyone going through this.
Note: I have been interested in this description since it seems to fit quite closely my experience. For instance, over the last few weeks I have experienced a very strong – almost unbearable, it seems – icky yucky feeling in the body. It seems to especially come up after going to bed in the evening. Before inquiry, it did seem almost unbearable. After inquiry, and the support it gave me in staying with sensations as sensations, it’s been much easier. (Not always easy, but easier.)