Feeling much more positive, I ran much more than I walked, my calves stopped hurting after 2.5k, still stopped and stretched when I felt them get tight but they were a lot less trouble.
Very eager to get that all running and no walking but I feel it coming, I feel stronger and my breathing is easier.
I'm not quitting!
On the bad side, I should have used my trail shoes, it was muddy and slippy. Luckily my normal shoes have decent tread.
Thank you to everyone here, the support is amazing and I promise that I couldn't have done it without you all.
ETA: it won't let me upload my photo of the flooded road lol