First the GREAT news: I nailed that first 30 minuter! I was careful to start slow, then taper to make sure I could do the whole thing without walking, and it worked! In fact, I felt amazing, right up until the cool-down walk (see next bit).
Bad news: Some hip flexor pain that I'd been ignoring for a while really flared up. By the time I got home I was hobbling. I'm sitting here writing this with an ice bag in my lap.
I stretch regularly after every run, and I never run on consecutive days. Anyone out there with any helpful tips, please??