Life and poetry

Why is it that when I have had to do poetry for courses I have found it incredibly hard, but now I am free to write what I want I have the urge to write an autobiographical poem? On Wednesday I started one about our experiences when son 1 spent almost six weeks in special care after birth. I suppose that the inspiration came because I have been wondering how much his start in life may have contributed to his current health issues. When it was all happening I thought I should be writing it all in a diary but couldn't bring myself to do so. I can write prose about things that affect me deeply, but prefer to fictionalise my experiences rather than write autobiographically, I like that little bit of distance especially if the work is for others to read. So why then am I writing about my life in a blog?!