I've found not questioning life is the best option to live it. Those who spend their time trying to understand it, will miss living it. I was like this. Now I try not to think about it very much. We cannot fathom why we are here, and for what purpose. If you're religious then maybe you can be convinced of what your religion tells you.

I agree, this thinking may be associated with depression, as depressed people see reality depressing, the so called depressive reality.

Even though we cannot understand why we are here, still we have a strong instinct to live.