What are Miss Havisham's reactions during Pip's declaration of love to Estella in Chapter 44 of "Great Expectations"?

While Estella looks at Pip during his poignant decalaration that Estella has been

part of my existence, part of myself.  you have been in every line I have ever read since I first came here....You have been in every prospect I have ever seen since...there and everywhere you will be.

During this declaraction of his total devotion to his love for Estella, Miss Havisham puts her hand to her heart, at first looking "by turns at Estella" and then to Pip.  When Pip expresses his deep love, his all-consuming love, Miss Havisham still covers her heart--

the spectral figure of Miss Havisham...seemed all resolved into a ghastly stare of pity and remorse.

Pip's open and sincere outpourings of his heart have touched a chord in Miss Havisham.  Dickens uses the words "spectral" and "ghastly" to denote that the feelings of Pip are the same deep affections that Miss Havisham, the young bride, felt on the day that time stopped for her.  Her heart remembers all too well the agony of this despairing love, the love that one would stop, but cannot.  She sees herself in Pip, and realizes that she is responsible for Estella's having no heart as she looks at Pip with "incredulous wonder."  It is at this point that Miss Havisham realizes the terrible mistake that she has made in fostering coldness and cruelty in Estella.