Part of the game is that there are unpleasant phases. The trick, as with everything, is to fully experience the unpleasantness, the fear, the angst, the anxiety, the nausea, the depression, allow it to be, surrender to it, and in that way become less attached to it, to let go of what can be let go of.
But it can be difficult to stay with such sensations. We want to escape it, to divert ourselves, distract ourselves. Meditation is a great opportunity to stay with what is actually happening. But even then we might divert ourselves into some tranquility that is present instead of dealing with some minor unpleasantness.
There is a sense here of exposing oneself to one's fears as a way of overcoming them, a prominent technique for dealing with phobias.
I recently saw the movie "The Accountant" (not sure I would entirely recommend it) where the central character deals with his autistic tendencies by exposing himself to loud, jarring music, flashing lights, and physical pain in an attempt to desensitize himself.
In my own case when I first started playing around with light and sound machines, mainly for the interesting flashing lights and the potential effects on brainwaves, I found the lights overstimulating. Sometimes it would affect my sleep. But over time, and perhaps after making some progress in meditation, the lights no longer bothered me. I got used to it, I adapted.
In the same spirit, I wanted to recommend some music that I stumbled across. It is the Realignment Series (free on archive.org) by Sister Waize, a series of somewhat dissonant industrial ambient music pieces. I find it evocative of the unpleasant states and useful for keeping one's focus to these elements and thus working through them.
Sister Waize's original instructions for listening to the music.
EDIT: A similar type of music, used in the Finders Course, was brought to my attention. This would be the out of print 1994 "Sri Yantra" by Jeffrey Thompson.