"Feel the fear and do it anyway" is a fave of mine
I also really rate affirmations and subliminals
I often play these ones from Power Thoughts in the background during my day
And these 2 I play while relaxing
I know you asked for books specifically but it may be worth having something like these on at times too as they get into your subconcious. They really helped me when I was going though a particularly low time in my life where I didn't have a great deal of self esteem / confidence.
Meditation and yoga also do wonders to connect you with yourself / self love - I have a link to the calm app for full access to meditations etc if you would like it