Why do we hue and cry, when we really know that at the end of the day, all amounts to nothing?

If I am understanding the question correctly then my answer is... Crying is a release of something whether it's pain, sadness, anger, frustration, fear, etc. So actually crying does help sometimes. It's like a pressure valve. If you don't release some of that pressure you will explode one way or another.

It all amounts to what you put into it and what you consider to be working towards something you PERSONALLY place value on.

For me, there is no "higher Purpose" or destiny. There is no "Fate" or concept of "You were meant to do or be this or that" . . .

We are the makers of our own destiny, by mere focus of will and the path cut into life's pathway by decisions we make to situations and circumstances that befall us. Looking back the path is always clear and seems to have purpose because we assign purpose to it.

If at the end of the day it's all still amounts to nothing then you are doing it wrong . . . Life that is.

Well, I disagree that "at the end of the day, all amounts to nothing."

So I can't give you a meaningful answer.

You are correct, if you have no alternative belief, then ultimately everything results in zero, people can only add meaning to something while they exist.  But when the world ends, it's beginning and middle will still have no ultimate meaning, no one to reflect on it, nothing.

sometimes in life we think our life is bad but there other people with worse problems.