i had that. every night right before waking up i would see my life and the world with crystal clarity - how everything that is good and all hope is an illusion and how all the evil and despair are real. it went away the same as it came. lasted a few months probably.
reminds me also how when i broke up with my 1st GF she kept appearing in my dreams and it went on for years and i thought it would never stop. but then it stopped. haven't seen her in my dreams in years.
i mean the world nor my life didn't get any better. it's just that sometimes the mind locks onto the dark things and sometimes it plain ignores them.
typically for me it is nutting to some good porn that does the best job of knocking negative thoughts out of my head.
or laughter.
but i also start laughing after nutting.
maybe that is why so many pornos are humorous - it seems to go together.