What am I?

[the_forsaken]

I've been slowly fading into the background it seems. Is this what is feels like to be invisible? This is a riddle. But it describes me. Or at least how I feel.

I'm something. I'm nothing
I am short. I am tall.
When you fall at your sport,
then I stumble and fall.
I have never been seen,
yet beneath a new moon.
I thrive in the evening,
but vanish at noon.
I am lighter than air,
I weigh less that a breath.
Darkness destroys me,
and light is my death.