How do I come to terms with the suffering? Please help.

My mum passed this year aged 59 after a 10 month battle with cancer.

I am really struggling to cope with the suffering she had to endure over these 10 months, particularly at the end of her life when I know she was in a lot of pain. I was just wondering how do I get past this? To hear at least she is at peace now and not suffering anymore doesnt really help me as I feel that she should not have had to suffer this horrific pain the first place and in a way she is still suffering as she is not here with us all. It really haunts me that she was scared to die at the end. She was literally the most sweetest kindest person in the world so I can't understand how something so horrific happened to someone so amazing? It is such a massive loss and she didn't deserve any of it. It makes me so angry and so sad. Any words of advice would be greatly appreciated. x