In chapter 49, Pip and Miss Havisham discuss Miss H.'s remorse for how she has treated Pip, and, more importantly, for how she raised Estella. By her own admission, Miss Havisham "stole [Estella's] heart away and put ice in its place." She says that she "meant to save [Estella] from misery like [her] own," but only succeeded in making her cold and heartless. After this conversation, Miss Havisham's dress catches fire and Pip puts it out.
During this entire scene, Miss Havisham says over and over, "What have I done?" She also pleads repeatedly for Pip to forgive her.