I have no idea of the origins of this word, so my understanding of it may be wrong, but where I come from its a phrase that means you're so completely tired that you're over tired or totally beat. I can only hguess its a reference to the fact that a lot of dogs seem to sleep a lot and thus appear to always be tired and in need of sleep.

Micro marriging is when your partner manages your personal day-to-day tasks with you much like a Micro Manager at work.