Actually, all of Sunday is my least favorite day. But it's at night that Sunday really bears down on you. The mail doesn't come and everything closes early and no one makes plans and then there you are, and it's November and the nights are a million hours long and it's COLD TOO GOD WHOSE IDEA WAS THIS.
I think it's safe to say that I have delayed sleep phase disorder, because I cannot get to sleep before three in the morning unless something unusual happens like I spend forty straight hours awake or I clobber myself into unconsciousness with a large dose of melatonin. There's really nothing that can be done about this, according to both science and me: some people with DSPD do have some success brute-forcing themselves into a more normal routine through a combination of drugs, light therapy, and rigorous observance of what is ominously termed sleep hygiene, aka going to bed at the same (normal) time each night, dimming the lights an hour before retiring, not drinking coffee after noon, and all the other little habits that are supposed to add up to healthy sleep -- but even those who manage it will be sluggish and unhappy during the day, because it just feels wrong. Seven in the morning is not for being awake. Seven in the morning is in fact the middle of the night. This is one of the reasons I became a freelancer all those years ago: I could not adjust to a normal sleep schedule. I would literally fall asleep with my head on my keyboard. And I was twenty. I certainly haven't gotten any more vigorous with the intervening years.
So for me winter is a lot like one uninterrupted night, and I find that discouraging. I like sunlight, and in winter the tilt of the Earth and my own personal programming arrange things so that I can't have any. Yet somehow Sunday night is worse than the rest of them. Things will be better tomorrow. Because I'll tell you something about freelancing: I've been doing it for what, fifteen years now? And that I don't have to get up and go to work on Monday morning still hasn't gotten old.