have not read the thread - apologies.
but having read your op, i just want to give you a great big virtual hug and say there is absolutely no point kicking yourself for something that couldnt be helped. you did your best with something, it didnt work out, you managed the situation with an (the) alternative. your baby is absolutely fine, and loved and thats about all she cares about.
sounds like pretty good parenting to me.
and if you have another, no doubt you will be better imformed and armed to get the help you need to continue, if you want to.
i am massively into breastfeeding - but theres no way i think anyone should for even a second, be berating themselves for things outside of their control.
i nearly 'gave up' with ds1 as well, and like to think that if i had, id be able to live with my decision. it was LUCK that meant we turned a corner and it got better for us, nothing i did that was clever or special in any way. now how does that make your actions and mine any 'better' or 'worse' than the other?
try to concentrate on all the wonderful things you can and no doubt do, do with your baby now and in the future, rather than wasting energy worrying about the past. and stop trying to be perfect, we none of us are.