Querulous is a adjective

Querulous means constantly complaining: whining

Merriam- Webster’s dictionary

“The Yellow Wallpaper” by Charlotte Gillman

“Besides, it is such an undertaking to go so far. I don’t feel as if it was worth while to turn my hand over for anything, and I’m getting dreadfully fretful and querulous. ”

I understand the concept of this word now. She is saying that she is starting to worry and its leading her to start complaining.