I'm not a doctor, obviously, and I'm not an expert on the human mind or all the various chemical and psychological processes that are ongoing in our bodies and brains. However, like a lot of people, I've noticed that humans in general seem to be pretty cyclical in many of our moods. Obviously this is the most pronounced in manic depressive / bipolar disorder patients, but from observation it seems like they just have a (much) more extreme version of what every person goes through to some greater or lesser degree. I think that OCD patients are also just very heavily exaggerated symptoms of some of the underlying impulses that we all have.
Why am I bringing this up? Well, because it's the first day of the week, and I'm dealing with my usual bout of depression that brings. Today is Tuesday, but yesterday was a holiday in the US so I wasn't working. Usually the depression hits me on Mondays, but since I was off it is instead hitting me today. In the movie Office Space, one of my favorite films, they refer to this as "A case of the Mondays," and that seems about right to me. Certainly when I was working in a physical office, you could notice a distinct atmosphere difference on Monday mornings in all the staff, even those who intensely loved what they do.
So what gives? What on earth do I have to be depressed about right now, for instance? Things are going pretty well overall, I'm mostly doing what I want to be doing and seem to be moving in the right direction for being able to do it fulltime, and I've just had some really happy news in my personal life this morning. Plus, even just yesterday, I was excited about the work I would get to do today. Why on earth should I instead be feeling like things are so bad, and so much is wrong with the world?
Oh -- wait, are you waiting for me to give some big reveal as to why that is? Sorry to disappoint, I have no freaking clue. I'm sure a psychologist or a neurologist could give a better answer. All I know is that it happens, and I don't have clinical depression or anything (the rest of the week I'm generally fine, except when something happens that would make anyone a bit down for a few hours). So the question, for me, is not why this happens but what to do about it.
I had thought that if I was more into my work, that I would not have this trouble. But, clearly that's not the cure because I get this even when I'm working on game stuff right on Monday morning. I think it might have to do with the transition. Even if I'm looking forward to the work, getting back into the work can be a bit daunting. You start staring at that huge forest, rather than just the individual trees, and it can be depressing just how much there is to do.
It might have to do with having too many options and too many decisions to make, I don't know. Normally during the week, I have a short list of items that I am going to hit next. Sometimes new items get slotted into that list ahead of the original items, but that's no bother -- you just roll with it. But somehow at the start of the week it feels like there are more options.
Maybe that's what it is, I don't know. The solution, for me, is simply to start small. Just work on some little thing, important or not, that I can finish in 5-10 minutes. There are plenty of tweaks of that size in my queue. That usually gets me going, but if it doesn't then I just do a few more of those. Within an hour or so, I've completed several small tasks, am in the right mindset, and am ready to move on with the rest of my bigger tasks. The feeling of being slightly off then tends to persist for a few hours, sometimes the rest of the day, but after that initial ramp-up period I'm back in the saddle and at least not hampered by it. And the rest of the week, I'm perfectly fine.
This is perhaps a bit of an odd topic to touch on, especially considering my usual subject matter, but I think this is an important issue. At first this cyclical start-of-the-week depression had me worried that something was wrong, that maybe this was not the right profession for me after all (despite all of the evidence to the contrary). I don't know how many other game designers also have this problem. I think it's a common thing amongst people in general, but especially the "creative types." I'm convinced it doesn't mean anything, it's just some sort of biological problem such as needing sleep/food, or having low blood sugar or what have you. Do what you need to do to move past it as quickly as possible, so that it doesn't cost you a whole day of productivity (who can afford to lose 1/5 of their work week every week to this phenomenon?), and don't read too much into it.
The social tendency to not whine and talk about things like this (just "suck it up") is unfortunate, I think, because it tends to make people feel very alone when they have this sort of issue. But, anecdotally, it seems to be pretty universal to me. Most people just assume it is because there is actually something wrong, such as a job they don't love. That makes people who normally love their job worry even more about things like this. To that I say: let it go. There is some sort of process going on inside us that neither you nor I likely fully understand, but it doesn't mean anything. "Looks like someone has a case of the Mondays" is, for whatever reason, not limited to people who hate their jobs. Once you realize that, the phenomenon is not nearly so alarming.