Stand-in

I'm a stand in actor, different from the general stand in, with a special nature of work, which is the most despised type in the whole studio.
Everyone looks at me with disdain, and everyone can put me under their feet.
Every day, I shuttle between the large fields, and I'm used to the bright and beautiful back, the corner where the sun can never shine.
I can't be spared either. At last, I fell slowly and couldn't extricate myself...