Oh. Just a quick note: I went for yoga class again on Tuesday evening: Hatha class with my hard-core Teacher M. My body isn't as strong as I would like it to be, and my legs were trembling a little after all the Warrior variations.
But it was fine. No dull pain at the navel - at least, I was careful not to overstretch. Side-twists are just fine too. Just have to watch myself, not expect too much from my body at this point, and just do it.
Tomorrow is another day to practice. That's all that is to the practice, isn't it - you just come back, one day at a time.