Wow, this could be a story in and of itself, so I'll keep it short here and maybe play with the ideas on my blog. The short version: it's hard for me to separate myself from my writing, the line between reality and fantasy constantly blurs.
The first story I remember sharing with other people was in my grade one class, I got selected along with one or two other students to read it over the morning announcements. It featured me travelling back in time to meet a cave-man ancestor and an anachronistic dinosaur. So I've always been in my fiction.
I told myself stories all the time through my childhood, whether in writing, using Lego or G.I. Joes or other toys. Conflicts and arguments in real life spilled into the characters, and the solutions they came up with helped me in my life, which was interesting. Character types that lasted across years strangely showed up in real life in the personalities of my closest friends, like I had been planning the type of people I would want to one day associate with.
So when I sat down to write my first book, No Man an Island, those themes became central to the story. The stories the main character grows up reading play themselves out in his life, and character traits from stories show up in his friends. Given the interplay between reality and fiction in the story, I put a lot of my own life into that character to further blur the line and strengthen the theme, so it's semi-autobiographical.
In the case of Diggory Franklin, I think there's a lot less of "me" in the character's behaviour and choices, but there are some parallels. His father died in the story in 2008 and my father died in 2009, which I did not see coming and there was weird signs of the way it affected me in my writing -- two weeks before he died, when we all knew his time was short because of cancer, one of my characters said this : "I don't think anyone really 'adjusts' to the fact their parents are dead. They just cope." and that kind of prophesied how I would handle things. The first line I wrote in Diggory's story after the funeral was "I coped with my status as an orphan a little better each day." His handling the death of his parents (which started in 2008 remember) dovetailed with me handling my grief a year later.