Just a retreat day. Do we let ourselves have it? Do we give our beloved a day off now and then? What happens, how do we feel when we're not "on" and productive? A day such as this now and then may be much needed rejuvenation.
(However, several weeks of this may indicate depression, and I recommend you exercise and meditate daily, socialize several times a week, even if you don't feel like it. And if these don't help, seek professional help.)