What is it about Sundays?

They usually start fine: Liane Hansen and the estimable Will Shortz on the radio, a few cups of coffee with my weekly dose of network TV bloviation, followed by a Bach cantata or a Haydn mass on the stereo, and then an hour or so with The New York Times.

But somewhere during the late morning or early afternoon, a weight begins to settle on my chest, a pervasive melancholy that evolves over the next few hours into something worse, a feeling of...I don't want to call it depression, since that's become a diagnostic category and may not apply, but certainly a burdensome and occasionally almost immobilizing despondency.  It's a feeling unique to Sunday, distinctly different from any sadness that might be felt on any other day of the week.  It's predictable, for one thing, and it covers the day in a gelatinous gray fog, it sucks joy and energy out of every endeavor.

And I suspect I'm not the only one subject to it.

But the reasons for it elude me.  When I first started to experience it--I think it was as far back as the fifth grade--it didn't seem mysterious at all.  School was going to resume the next morning, and I disliked school.  Reason enough.  In junior high, there was added to this the realization that I hadn't done my weekend homework when I should have and would now have to do all of it after Sunday Night at the London Palladium (England's amateurish answer to the Ed Sullivan Show) ended at ten.  In high school, there was added to these other things the distress about all my grand hopes for the weekend having come to naught.

So, for several years, melancholy seemed like a rational response to everything Sunday was serving up to me.

But it's been decades since I attended school.  There are no longer any classes to dread on the morrow, or homework to worry about and desperately rush through at the last minute.  Nor do I even have to face the substitute regimentation of a job;  like many writers, I make my own hours, no one is looking over my shoulder, and I'm as likely to work on Sunday as any other day of the week.  And of course my Friday hopes are no longer so extravagant or so implausible as to taunt me with their futility when the weekend finally winds itself down.

But none of that helps.  If anything, the feeling has gotten worse as any conceivable justification for it has ceased to exist.  So...is it simply a carry-over from my youth, an impacted vestige of a no-longer-relevant emotion?  Or is something else going on?

Do any fellow-sufferers have a theory?