Can't decide if I am an atheist or just incredibly pissed of at God. I can't accept that any God that gives a damn about us would allow what happened to a woman as selflessly giving and widely adored as my mother, she died after long and horrible suffering, can't forgive him/her/it for that, easier to just consider the universe empty and meaninglessly chaotic.
Im sorry to hear about your mother. You will see here again someday.
And if you are pissed at Him, feel free to talk to Him about it. He isnt going to hate you for being angry at Him. He loves you. He wants you to be happy. When and if you ever become ready, He will welcome you with open arms.
I know you feel right now that you could never forgive Him. And you might not. But my experience with the Spirit tells me that when we feel the love of God touch our hearts, all the anger, bitterness, and pain are swallowed up in that love. I know when I feel the Spirit, it doesnt matter how I felt even five seconds before, I cant feel anything but love toward everyone. It's a marvelous experience, though i suppose it kind of sucks when you want to stay angry. Ive learned that I would rather not even if i temporarily feel like i do though.