I'm really sorry for your loss. I had a great grandmother who passed from the same disease a few years ago. Cancer is a truly terrible thing.
Losing a loved one hurts so much and - at the time - you only wish to escape. You'll always miss them, but it gets better, and they never really leave you as long as you remember them. Once you've moved on from the sadness, you're left with lovely memories of them and the legacy they've left.
Best wishes X