Death on Garden Bloggers Bloom Day

For me, Garden Bloggers Bloom Day is a bust this month. This poinsettia has been living happily on our dining table, in front of a big southern window since Christmas.  At night we close the lined curtains, to slightly moderate heat loss. I've kept it watered, but yesterday I came downstairs and when I opened the curtains I saw that it was withered and drooping. I don't think it was below 32 degrees in our living space, but…