No insulation maeve? None in the walls either?

Well, soon enough, albeit none too soon, you will be able to cozy up in the yurt.

I understand that Maine winters and North Carolina winters are different creatures, but the six years we lived in the Airstream without underpinning or skirting were pretty tolerable, and temps in the 20's and teens F at night were not uncommon. We used a radiant propane heater we turned on in the mornings to huddle in front of, and to take the essential chill off of the front part of the trailer at night. Wool hats and socks were our friends in the evenings while I fixed supper, and we retreated early to the bed to cover up with a combination of heavy wool Hudson Bay blankets and down mummy bags. Would set the alarm about 30 minutes early to get up and light the heater, then dive back into bed until the deep chill was off the kitchen/sitting area. (We also spent one winter in a tent. We got through, but the travel trailer was much more tolerable when we graduated to it.)

I think the main thing, in either setting, was we were very careful to dress so that we kept reasonably warm during the day and did not allow our core body temps. to drop.   I'm allergic to wool, but nothing works better to maintain body warmth when one is not out working up a sweat. The new synthetics are "active wear" and are great if one is outside and active, because they breathe. None of them provide enough to maintain body heat in a cold, indoors setting.   They are not designed for outdoor living, but for outdoor activity.

Wool or not, wear a cap to bed, and as many clothes and covers as needed to stay warm in bed. Warming the bed with a brick or rock is good, but you still need enough insulating bed and head cover to maintain body temps. through the night. Go to bed before you feel significantly chilled.

And I bet you know all of this already.