i dont have a book suggestion, but i just wanted to chime in as i've been having similar feelings the past year, and i kind of had an epiphany the other day while at a yoga workshop. the theme for the workshop was about courage and confidence basically. and what he said was that most of us feel that we need confidence first to do something courageous, which is how i've always felt. and because of my low self esteem this past year, i feel like i cant accomplish anything etc. but his point of view was this:
courage is doing something we are fearful of, and by taking that step to do that courageous act, we gain confidence by accomplishing or at least attempting the thing that once feared us.
so i dont know if this has any relevance to you, but for me, it could be as simple as getting out of the house that will feel courageous for me, or going to a class for myself, or making a lunch date with someone. but i have realized that others cant give me what i need, i feel very lonely and wish i had more support, but nobody can really give me what i need emotionally until i help myself.
i hope this helps a bit.