She was afraid - truly afraid - that Qin Zhiyou would completely abandon her and return to his family, return to Lu Weixi's side. If that happened, she would be without any remaining chances.
She accepted Qin Weijia's financial support, but she was still unwilling to let go of Qin Zhiyou. On top of that, Qin Weijia kept issuing orders to her, leading her to hold onto him even tighter. Qin Zhiyou had been aware of what was happening, but he had the vague feeling that Qin Weijia was about to make a move - even their son's wedding and daughter's happiness were being negotiated, it was unlikely such a chess piece wouldn't be used to their advantage.
She was not the same as Qin Weijian. At least Qin Zhigu had some abilities, some fame, but her own son and daughter were useless. If she didn't try harder, she might end up with nothing in the future.