I will do a longer recap once home, but the headlines:
First 10k on target. Then my calves got super stiff and sore, no idea why. So I slowed down. Found it really hard, I cried when I got to the stadium and when I got my medal! Official chip time is 5.21.59, so very very pleased.
Thanks for all the comments- I was thinking of all your encouragement on the way around!