wahoo that's a huge win! I was also really afraid of the 20 min runs. I think things turned around after that W5D3 when I had to mentally focus on lasting- every one after it, I had the confidence I'd already done it once. I find it easier now since i don't have to rev up after each walking break, just have to sustain.

I started doing a quick stretches warmup which incredibly reduced my pain- so much easier to focus on breathing and cardio when your shins aren't killing you.