RE: Music & Darkness
That's a great experience you went through. Once such is revealed to you, you can create a similar session in maybe similar settings. Nothing lasts forever indeed, but nothing has to be a one time only thing. The first step you took, may be discovered by chance that darkness is for you the way to dig deeper into your own mind and soul. Now you know this, you have the tools at hand to progress, to re-create.
Though darkness can do similar things as your experience, to me, similar (or same) works for me when listening to a specific kind of music, in settings that doesn't have to be dark... this can be in a club, or just outside in a park. Throughout the years I got to learn a few different ways, hence my toolbox is well equipped :)