Why does Rosemary not want to go to work in the morning?

From the text:

Mom had the same problems she'd had in Battle Mountain with organizing her paperwork and disciplining her students. At least one morning a week, she'd throw a tantrum and refuse to go to work, and Lori, Brian, and I would have to get her collected and down to the street where Lucy Jo waited with a scowl, blue smoke chugging up out of the Dart's rusted­through tailpipe.