Jonny, I have a personal sense of their pain. My mother abandoned me when I was an infant. To this day, well into my middle age, I ache for her. I'm crying right along with you.
I just went to a funeral last week for a friend's husband who also passed away suddenly. At 57, he was much older than Tammy. But the shock is the same. He just went to work one day. After awhile, he suddenly went down on one knee, fell over on his side and died. His wife is waiting for the full autopsy results, but she believes it was a massive heart attack.
Never, ever let a day go by when you fail to tell those closest to you that you love them. Live life to the fullest and don't sweat the small stuff. Howevever it happens for us, we are each on the same path to death. Life is a precious gift. Although her life was far too short, Tammy did good things with hers. Her two daughters will live to bear her grandchildren, and from heaven, she'll be their guardian angel.