no trouble discerning the mood of this one, as your title leaves no room for debate. I understand the feel of it, because I often feel depressed at the change from bucolic summer to the approach of winter. I think that the spareness of the lines and the tapering of them to the end brings a bit more emptiness to the feel. Good job of bringing that out here with very few words.
~ Geezer.
.

Hello, Rula!
So good to see your poetry! I agree with Geezer's comments. Also, I felt that "leaves" used as the last word in your poem had extra depth in meaning - as a departure in some way. Very quiet.
Thank you,
Lavender

Autumn leaves
but gradually
when you are depressed
think of the bare tree deserted by every leaf
till winter comes and goes
it then snows

let it be so
you just participate
another fresher golden leaf
as spring springs in

O lalalalaaaa