I might be having a midlife crisis. But, as in all things, especially regarding a pseudo-science concept such as this, the more you examine it, the more you can convince yourself that all this stuff is True and Happening. It's why fortune-tellers and horoscopes and precognition remain popular - the observer effect is well known (and, unknown to me but submitted by sbp: the Forer effect).
If we take Wikipedia at face-value, I don't feel this has anything to do with "the passing of youth and the imminence of old age". I'm 31, but I feel like a young'un. I have to think about what my age is, and I do so not because it's rote but because I have to calculate it every time from the year I was born. When you grow up without birthdays, you just don't pay much attention to age or years. Nor has anything major happened in my life lately, unless you consider the birth of my first child, three years ago, and my second, one year ago - I certainly consider those major events, but positive ones, not like "death of a spouse" or "career setback".
When I look at all the things I like to do (which is an awful, awful lot - I haven't been bored for decades), I don't find myself getting the same amount of satisfaction I used to. I feel "paralyzed", unable to sit down and "do something", but not from laziness nor lack of impetus. This applies both to existing projects or new attempts of existing interests (writing a new program or book, starting a new game, etc.). I don't have any "new" interests that couldn't fall into a subset of an existing desire, nor would I have the time anyways.
The lack of time is a contributor, I think. In a 24 hour day, I sleep 6, work 7, and "babysit" for another 6.5. Let's fill up another 1.5 with maintenance (eating, showering, responding to e-mail and other computer-y things). That leaves me three hours of the day for myself (I will ignore rebuttals of "OMG, YOU HAVE FREE TIME?!!": I'm not comparing myself to you, asshat). In that remaining time, I'm supposed to "relax", "wind down", and "enjoy myself" (my beliefs). For the past week, and on and off for months, I've merely wandered around the house or sat in a chair staring into space. Sometimes I'll meander idly around the web, wasting bandwidth.
There is plenty to do and plenty that I want to do, but it seems that by the time I start to do it, and really get into doing it, time is up, time for bed. I never reach that point of being "in the zone"; my free time feels like an endless series of false starts that may culminate into something worthwhile, but eventually peters off into trying to figure out what I was thinking 24 hours ago.
Maybe I'm "just in a rut" - I've been in those before, but never this long.
Part of my problem may be because I try to make everything a "project", something that I would be proud of "releasing". That perfectionist mentality got me to where I am today but, back then I had a lot more free time. As an example, one of my latest "longest journey" goals is to read every Star Trek book ever written, something approximating over 1,000 entries. A lofty goal, certainly, but I couldn't leave well enough alone: I've convinced myself that I should do "something worthwhile" and contribute summaries and so forth to Memory Beta. Even though I love reading the books, I almost dread finishing one because it means I "have" to improve the wiki, something that would take me a few three-hour nights per book. It's easy enough to say "well, don't do that", but the researcher in me chastises me for "keeping the data all to myself". I'm fighting myself over being a leech or a contributor.
One of the oldest projects I've kept wanting to come back to, time and time again, has been a browser-based game. I've started coding dozens since I first wrote about them in 2000, but they always reach a point where I lose interest: I know I'm a better coder than most people, and I know success is inevitable. Coding nowadays, for me, is like cutting and prepping ingredients for your favorite meal: it's busy work and my mind wanders. I know I can do it, I take no pleasure in it, and it's rarely a challenge. Given enough time, I'll succeed, and keeping it maintained with the latest framework releases will seem like work and a waste of time. I prefer story over mechanics anyways, but I don't even feel like I have enough time to run a decent play-by-post RPG.
Nearly everything I like doing, and I've examined them all, doesn't seem worth actually doing anymore.
I can't even be arsed to write a decent conclusion to this posting.