Don't mess with the Fat Concubine; she's powered by a five-core engine

Lin Xiaoxiao, a modern Chinese medicine doctor, is reborn as the fat princess Zhou Qingxian. On the wedding night, she accidentally breaks the leg of Prince Feng Linyuan and is abandoned, after which she gives birth to quintuplets. Five years later, she loses weight and practices medicine while raising the children alone. Feng Linyuan comes to seek divorce but is instead tricked into getting closer by the children. Zhou Qingxian enters the palace as a medical woman and secretly treats the prince's leg. The two experience life and death as well as conspiracies, and their feelings gradually deepen. Eventually, her identity is revealed, and after learning the truth, Feng Linyuan chooses to accept her, remarries Zhou Qingxian, the vicious female supporting character is punished, and the family of seven is reunited.

Synopsis from DramaGo.