First, my deepest condolences for the loss of your daughter. There are few things harder than for a parent to lose a child. It is no wonder that you are having such a difficult time.
As for your sister: I can only guess that there is something about your loss that is triggering regrets and griefs of her own that she simply can’t handle. The accusations she is leveling at you may be “projections” — things she feels about herself. If that’s the case, there is no way for you to deal rationally with something that is deeply psychological.
This is complicated. I suspect that she, like you, was abused as a child. Unlike you, she may not have recovered enough to parent differently from what she herself experienced. She has to come to terms with the fact that she has a living daughter that she failed when the child was only 14 while you are grieving a daughter you loved and parented in ways she couldn’t do for her own daughter.
Please stop looking to your sister for comfort at this time. That emotional well is (at least for now) empty. Arguing with her (or explaining, or even sympathizing with her) isn’t going to help either of you. You can and should grieve in your own way and with the support of people who can support you. There is no reason to hate yourself. There is no reason to take in the venom that is a reflection of your sister’s issues, not yours.
You didn’t mention whether your daughter’s father is in the picture. If so, I hope the two of you can comfort each other. If not, I sincerely hope you have a good friend or two who can support you in your grief. If you don’t have friends who are emotionally available, please consider seeing a therapist to help you during this very difficult time. A therapist can provide a place to feel your feelings and to heal.
I wish you well.