This is not childish. It means you have no purpose in life. If you feel life is not worth living, find purpose and you will feel better. "Make more life", "make life more bearable for me" and "make life more bearable for others" are good universal ones, to have a starting point. If you don't like them, find a better one. Of course, if you DO want to be unhappy, please continue as is :), accumulated unhappiness sometimes leads to big things.
This wasn't about me, more about a "one". I am sure most have had such thoughts. I know what you are saying, but my point is that none of us are voluntarily here. I was told by my grandma I was an accident :) Accident our not, you hatched from the egg, now go find purpose.