Billionaire after Abandoned

For eighteen years, I had been giving blood transfusions to my sickly younger sister, practically becoming her "mobile blood bank." The countless needle marks on my arms bore witness to my sacrifice. However, at my sister's coming-of-age ceremony, she not only stole my boyfriend but also revealed a secret to me—I wasn't even my parents' biological daughter! I was kicked out of the house and sent back to my poor biological parents in the countryside. When I returned to my biological parents, I discovered they weren't poor farmers at all. On the contrary, they were incredibly wealthy and powerful tycoons! I instantly became the daughter of the richest family! My sister and adoptive parents were filled with regret when they learned the truth. They came to me, knelt at my feet, and begged for my forgiveness. How should I punish them?