Sunday dread is usually read as a sign you are in the wrong job. Sometimes it is. Often enough it follows you into the next one, and it starts on Saturday.

It does not wait for Sunday night. It arrives some time on Saturday afternoon, usually while you are still doing something you were enjoying.
A small drop in the chest. A slight loss of interest in whatever is in front of you. Nothing has happened. The week is still two days away.
By Sunday it has a shape. You go quiet after lunch. You start doing small jobs that did not need doing. Somebody asks what is wrong and you say nothing, because nothing is.
The advice for this is well meant and it is everywhere. Build a wind-down routine. Plan Friday so Monday is not a cliff. Put the phone in a drawer. Line up something on Sunday evening you actually want to do. Protect the weekend.
Some of it helps. Half an hour on a Friday writing down where everything stands does take weight out of Sunday, because a vague week sits heavier than a known one. Keeping work off the phone after six gives you evenings that are genuinely evenings. None of that is wrong.
It is the louder version that needs looking at properly. If you dread Monday, you are in the wrong job. Leave.
Sometimes that is exactly right, and it has to be said first, because the alternative is telling somebody to manage a feeling that is reporting something true.
There are places that grind people down. Understaffed rooms where the work cannot be done in the hours given, so you finish every shift having failed at something. Managers who make people feel small as a matter of habit. Rotas built with no thought for whether anyone can sleep. If that is where you are, the Saturday feeling is not a flaw in your character. It is accurate reading. And leaving, where leaving is possible, is often the entire answer.
For some people it has gone further than dread. The weekend arrives and nothing in it lands. You sleep in and wake up just as tired. Two days off that put nothing back, and by Sunday lunchtime you are already counting what is left of them. That is worth taking seriously on its own, whatever you decide about the job.
So the advice is right about a good number of people. It is what happens to everyone else that is worth understanding.
You have probably watched it. Somebody moves to the better place, the shorter drive, the manager who is decent to people. The Sunday feeling goes, and for about three months it is properly gone. Then one Saturday afternoon in March it is back, in a job they chose, with people they like.
Nothing in the advice explains that.
It shows up in other places too. People who like their work get it. Nurses on a Tuesday to Saturday week get it on a Monday night instead. Students get it in late August with no job at all. Retired people get it before a visit from family.
The feeling is rarely about the tasks. It sits on the handover: a stretch of hours where you have some say over what happens to you is ending, and a stretch where you have very little is starting. The body registers that shift long before you get anywhere near a diary.
There is a second part, and it is the one people miss. Monday is the first place anything unfinished can go. The thing you should have said on Wednesday and did not. The message still sitting unanswered. The task you have moved down the list four weeks running. None of it can be dealt with on a Saturday, so it queues, and the whole queue arrives at once.
Monday is where it lands. It is not where it comes from.
Which is why the wind-down routine only half works. A bath, a film, an early night. It lowers the volume for an evening and settles nothing, because none of those things touch the queue. You get through Sunday without looking at what Sunday is carrying, and Saturday comes round again six days later.
The timing is the giveaway. Saturday afternoon is not a reasoned conclusion about your workload. It is learned, and it runs on the clock rather than on thinking. I work with people who have changed jobs twice and brought the same Saturday afternoon with them both times.
Look at what the feeling is actually attached to and it is almost never forty hours. It is one conversation you have been putting off, or one person whose mood you cannot predict, or one small thing you got wrong in front of others and have not put down since. The worry that runs ahead of the week is seldom about the week. It rehearses one scene in several versions, and the version that happens is usually none of them.
That is oddly good news, because a conversation can be had and forty hours cannot be argued with. Most people, when they write down what they are dreading, find something that would take five minutes and has been taking up eight days.
There is also a version of all this where the advice makes things worse. Protect the weekend, plan the wind-down, pick the right Sunday evening. Now Saturday has a standard to meet as well. When resting becomes another thing to do properly, the two days start to feel like the week, and the drop in the chest arrives on schedule anyway.
What changes it is not talking yourself out of it. The feeling is not irrational and arguing with it has never once worked. What changes it is dealing with what it is pointing at, and then, underneath that, the older habit of treating being answerable to somebody as a thing to brace against rather than a normal part of a week.
That habit is usually much older than the job. It was set somewhere it made sense, and it has been running on the same schedule ever since, whoever you happen to work for now.
It will still arrive on Saturday for a while. The timing does not update quickly.
Then one week it comes late. Then it comes small. Then there is a Saturday afternoon you get all the way through without noticing, and you only work out on Tuesday that nothing dropped.