Behind These Angelic Tears

Y/n has been bullied for years about being put up for adoption. The only thing Y/n had from her birth parents is her first name. A lovely couple adopts her into their family, and gives Y/n a younger sister. The family is inseparable, the sisters were the best of friends as well as supportive towards each other. Y/n and her sister told each other everything, that is up until Y/n kept a secret that threatened her very life from her beloved sister. What happens when that secret becomes too much? Will she be able to fix it on her own or will Y/n need to expose her secret? What will her family think if she tells them?