The phrase "dark tunnel" usually refers to a difficult or challenging situation where there seems to be no hope or positivity. It symbolizes feeling trapped, lost, or uncertain about the future. Full definition
No mom should have to go without access to a book that may just help her see the light at the end of a very dark tunnel. (mypostpartumvoice.com)
I'm just trying to get some light in my relatively dark tunnel, for lack of a better expression. (biggerpockets.com)
Even though financial benefits may be available for survivors of a traumatic brain injury, it can seem like a dim light at the end of a very dark tunnel. (kahlerlawfirm.com)