It’s been about a month since our last Yoga Shabbat, and I can’t stop thinking about it. Especially today, on the eve of Tu B’Shevat. I remember that moment in the service when we gathered in a circle, at Nancy’s instruction, and formed a stand of trees. Each of us, some more tentatively than others, assumed the Tree Pose. I was particularly self-conscious about how unsteady I felt on one foot. “Remember,” Nancy said in…