Will I be punished for neglecting my work due to having to stay with my sick mother and being unable to leave her alone, knowing that I am her only daughter?

The mother's right is immense, and showing her kindness is among the most obligatory duties. Her service and care are incumbent upon all her children. Your devotion to caring for your mother, who needs care, is among the best righteous deeds. However, it is not permissible to fall short in performing work that is obligatory to be done as required, as long as you are paid for it. If it is not possible to combine work and caring for your mother, then you should either request leave or resign if it causes no harm. Caring for one's mother does not exempt one from fulfilling what is required at work. The phrase "work is worship" is not entirely accurate; rather, work becomes worship if it is an act of drawing closer to Allah or if it is permissible and intended for the sake of Allah.