I happen to be an odd fellow. Years ago I took a leadership evaluation. It dealt with both skills and personality factors. One of the personality things that came out was that I am both highly introverted and extroverted. Usually, of course, a person is weighted towards one or the other. In my case I can get re-energized by either situation, and to some degree I naturally seek out the method that I need at the moment. There is some discernment needed though. For instance, sometimes I am in a writing mood, and getting alone in the studio is productive and energizing. Sometimes though, a retreat when I am feeling low, which actually amounts to navel gazing and is not helpful. In the book that I have referenced a few times here, "The Happiness Advantage", I was reminded of the fact that those with a healthy social circle are happiest. In fact, those who rely on their social circle in tough times fair much better and bounce back faster than those who do not. So if you are having a tough time, don't retreat, engage.