Qingmei Turned into a Yandere, I Must Have Contributed a Lot.

[No system + no rebirth + single female protagonist + sweet and sharp + yandere] "Li Yunyi, I thought that as long as I was good to you wholeheartedly and as long as I was pregnant with your child, I could bind you to me. But I was wrong. Before I could say anything, I fell down. I was too naive. Li Yunyi, you are like a beam of light that illuminates me every time I am in darkness, but you abandon me when I think I can embrace the light, so I can only fight for the light that belongs to me." Chu Xin hugged Li Yunyi and said, but her eyes were filled with pathological madness. Yun Yi, as long as I imprison your light, you will always be able to illuminate me. (You may not be yandere enough before you turn black in the early stage, but you will be completely yandere after you turn black under the stimulation of the male protagonist)