I am very sorry for the extremely unfortunate incident that has occured. I am not sure but I well and truly think you were doing the right thing, trying to help her. I myself am still a teenager, so I do not know much about the adult world. If it was me, I would have definitely helped, wanting to get her to be happy.
My advice: Never forget about your mother and the way that you cared for her. You will be even sadder if you do. Also, maybe you can try and go back into life in some way.
If my advice was completely rubbish, then I am sorry because I have never been in this kind of situation. I know it must feel horrible to know that she's gone. It's happened to me twice before in life with two different people and I still really miss them.
Hopefully on WrongPlanet you can talk to some people like moi and then you can relate to them, I hope that helps, getting to know some people.
Sad for you, mightyzebra
I hope the glass will be half full for you!