Angry at God, please help.

I don't get it. I just don't understand why everyone is suddenly having success stories with overcoming cancer, but yet he took my grandmother. I'm not saying I'm not happy for them, I'm over joyed! But why does he pick and choose who to heal? Did we not pray hard enough? Did she not have any faith to heal her? Why? Why can people say "see! God heals cancer!" Yet he leaves out a major population suffering. I miss her so much. Sometimes I forget that she's gone and I break down and just sob for hours. I don't know what to do.

How do I forgive God? I know that sounds ridiculous but I feel so lost and upset. How do I feel okay again?