There's Actually a Name for What I Do

NYT: Segmented Sleep

Here's more: Segmented sleep, also known as divided sleep, bimodal sleep pattern, bifurcated sleep, or interrupted sleep, is a primarily biphasic sleep pattern where two periods of nighttime sleep are punctuated by a period of wakefulness. Along with a nap (siesta) in the day, it has been argued that this is the natural pattern of human sleep in long winter nights.  A case has been made that maintaining such a sleep pattern may be important in regulating stress.