Not following through/trouble with sustained motivation

I signed up for a 10k with a plan to get back into shape. I didn’t train and it’s tomorrow and I’m feeling guilty, beating myself up, etc.
I want to respond to this in a way that I’m not beating myself up but not letting myself off the hook completely either because I see doing so as cultivating a habit of not following through.
C- didn’t train for 10k
T- how did I let this happen again
F-Guilty/mad at myself
A-question why I signed up; recalling times where I’ve signed up for things and not follow through; debate whether or not to show up and walk to cultivate trust in following through
Result-stuck; not sure what to do

C- didn’t train for 10k
T-I wonder why I signed up but didn’t train; what can I lean from this/do differently next time
R- use it as a learning opportunity

I’m struggling with the corresponding thoughts, feelings and actions for the result I want to create.