grope in the dark
1. Literally, to feel about without the use of one's eyes, as due to blindness or an absence of light. I was groping in the dark down in this basement for ten minutes before I could find a light switch.
2. To seek (something) in a blind, aimless, or uncertain manner, especially to find a solution, meaning, or sense of purpose. We've been groping in the dark for a way to pay our mortgage, but I just don't see how we'll be able to afford it. Pretty much everyone gropes in the dark at some point or another, trying to figure out the meaning of life.