firstly i want you to stop thinking that you failed!! i dont think creating a gorgeous baby, no matter how its birthed, is a failure on your behalf!! i think you did a wonderful job nourishing, protecting and nurturing your baby girl, something i think is the most beautiful thing a womens body can do, you didnt fail your baby in anyway! i understand she didnt arrive in the way you wanted and im sure next time you will feel more educated and empowered to give birth via a vbac.
i didnt get the birth i wanted first time, had PND but i did everything i could second time to achieve all that i didnt first time, i had similar feeling about the guilt i had after DD1 was born but i never felt guilty for wanting it better second time. i felt I was failed, not that I failed, i never felt that what happened first time was a failure on my behalf, i know i didnt have a c/s but i had similar feelings, i think you should proud that your going to do your best to achieve what your striving for!
i admit that i have let go of alot of the negetive thoughts that i had, once DD2 was born!
i highly recommend getting a doula, a student doula even! the extra support is invaluble! find a lactation consultant you can build a relationship with before bubs is born!
goodluck hun, i know you can do and you will do it!