I'm guessing the anger is normal and understandable.
I also think that when you have lost someone so precious that tbh nothing else is as important.
You said that she spent the last 5hrs of your DDs life there when she was not wanted. I know that you are focussing on your own DD having told her she was not wanted there, and her not respecting those wishes, but you too felt somehow you couldn't speak up and say Ok love, time to go, this is the end, it's me and my daughter only now and ask this woman to leave.
This woman is clearly not worth it. The weeping and wailing in itself is irritating to the point of murderous.
This will pass, you do have to let the anger go, it's only doing you harm and you have suffered enough.
So, to go forward, let the SM and her histrionics go.
In memory of your DD, resolve to spend time with those that bring joy to your heart and find the courage and strength to stand up to people not respecting your boundaries.
Perhaps bereavement counselling could help. I hope that you find your voice, and that somehow you can find some way to be happy again.