Hmmm, could she be wanting attention; a redirection towards herself?

It sounds to me as though this woman is an acquaintance and not a friend. Are you required to include her or be 'friends' on Facebook? This may come down to your confronting her about her hijacking your facebook feed. You may have to tell her that if she can't be more positive, she won't be included at all.

If she were a friend, I would think she would be sharing in your joy and celebrating your accomplishment.