Cracks, HUGE cracks!

[lgreco6]

Hey All, I built my third wfo last fall finishing late November. We are in Cedar Rapids, Iowa same latitude as Chicago. I had probably a dozen fires before things got really cold in early January. Got up to 1100 degrees in 90 minutes. There was no cracking at all but a tiny fissure on the front. Then I didn't use or look at the oven until this weekend. As you may know we had a brutally cold polar vortex kind of winter. When I checked it out this weekend I was shocked to see these huge cracks. These are not the result of bad curing.I did that as prescribed o FB website over the course of a week. My theory is that even though I had a dozen fires, there is about 30 thin layers of concrete and vermiculite (more for shaping than insulation). I think all the moisture did not get out before our wonderful freeze thaw cycle hit. Any ideas on what I do now? Your help would be greatly appreciated.