help finding a manga

I remember reading something here about a girl (possibly reincarnated into a book) that gets gifted a slime monster from her evil??? knight??? brother and named it Slime. I think I remember the slime lowkey having a crush on her and wanted to become strong to protect her.. imcryign. I think I also remember her step mother and sister hated her and had her living in a small room and unfed

HOPEFULLY THATS ENOUGH TO GO OFF OF!! PLEASE HELP ME I CANF GET IT OUT OF MY HEAD Σ(っ°Д °;)っ