I am glad to hear you are managing to feel a little more positive, and the more time that passes, the better you will feel, I am sure.
I suffered terrible guilt after Hayden was born - I went for induction at 41 weeks, due to polyhydramnios, and it completely failed, then - because of all the extra fluid he had in there he got himself into an oblique (diagonal) position. There were discussions with my consultant, and due to the greatly increased risk of cord prolapse if my waters broke, and the fact that induction had failed anyway, he recommended a c-section, and I went into theatre that afternoon. The actual section experience was pretty awful in that I felt pain during it, and lost a fairly significant amount of blood - not quite enough to need a transfusion, but enough that I felt totally drained afterwards and needed to take iron for several weeks. I then had terrible trouble breastfeeding and was readmitted to hospital when Hayden was a week old with raging mastitis and a uterine infection.
All this added up to me feeling like a complete failure as a mother - I failed to go into labour, failed to give birth, failed to feed him properly, and failed to look after him properly due to all the complications of my recovery. I spent his first few weeks of life on the verge of tears, and my poor hubby didn't know how to help me. There were times when every time I looked at Hayden I would cry because I had failed him so badly. I struggled with the fact that it wasn't really a life threatening emergency, and perhaps if I'd held out a bit longer I would have gone into labour.
Now, Hayden is over 2 years old, and although I would still rather have had a different experience, it really doesn't matter one bit. Yes, perhaps I would have gone into labour. But perhaps my waters might have broken and his cord prolapsed. In that case my decision to agree to the section when I did might have saved his life, just like your agreeing saved your daughter's life. We absolutely did not fail our babies - we made a big sacrafice for them, and put their well-being before our own, which is such an important part of being a good parent. We could have insisted on doing it the 'natural' way, but actually that would have been selfish, and could have been disastrous for our babies. So hold your head up high and be proud of what you did for your daughter. You made her, you grew her, and you did what you had to do to get her out into the world safely. You gave life to her, and you gave birth to her.
I am now expecting my second baby, and have been diagnosed with gestational diabetes, which means that if I don't go into labour, I will be booked in for an elective section at 39 weeks. I will admit I am a little worried about how I will feel if it comes to that, but I am getting my head around it and I will once again do whatever is best for my baby when it comes to making the decision.
One thing that has really helped me is to think back to before I got pregnant, when we were planning and TTC, and to remember that we were planning children, not birth experiences. Of course, it's natural to then start to plan for the birth experience during the pregnancy (mine was going to be a completely natural, drug-free waterbirth!) but it's not the main point of it all. I believe there is a grieving process of sorts to be worked through when things don't go as we hoped, but that time genuinely will heal and you will get through it and come to terms with it, and maybe eventually not even think about it.
Congratulations, and enjoy your precious little bundle you have worked so hard for xxx