I'm glad that NaNoWriMo continues to work for people, but I think it's important to note that it doesn't work for everyone - and it's ok if it doesn't work for you.
I attempted it twice in consecutive years about a decade and a half ago, and not only failed to complete anything, but was also driven into a worse depression because of it. I had to avoid people talking about it in November for years afterwards or I'd start to relapse, too.
It being November is especially hard on US people with any kids or large active families, dealing with big Thanksgiving plans.
No matter how well you plan, you really only get two meaningful weeks before the wall hits you. "Just set a reasonable word count to hit every day!" Then each day you miss days because your side dish plans went sideways or your flights get rescheduled, making the goal steeper every other day.
"Use your travel time to write more!" Almost impossible with young kids without sticking a spouse or relative with watching them, and the resentment of even asking if you can ignore kids to write lasts a hell of a lot longer than November.
"You can catch up after Thanksgiving!" Not after anti-vax Aunt J gives your family the gift of some great new viral disease that hits in the last week.
There are writing sprints in other months that never seem to have the community of NaNo, and all your single or childless writer friends burn it all out during NaNo. The community is a big part of what makes it fun, otherwise it's just an arbitrary chore goal.
December is not any better. There's nothing like hating your family and their dumb "let's be together and make happy, everlasting memories" ideas when all you want is to debug your A* algorithm for the Advent of Code.
Writing this much seems to take significant mental energy, so if you are already prone to depression you need to be extremely prepared. It's also true depending on your intentions for all creative things, particularly if you have low self confidence. For example you might feel bad about yourself because you don't do enough art so you enter some kind of art competition, but then you immediately feel shitty about yourself and so you can't bring yourself to do it, leading to even worse self confidence about it.
My therapist told me that in Germany there is an idiom that in English translates to "if you want to prove that you will fail you will always succeed". If I did NaNoWriMo, I would have the full expectation that I will fail, even if I try to tell myself that I have hope it would go well, and so I will just naturally make myself fail.
not sure if this fits here, but just today the thought occurred to me that depression may be related to expectations i have of myself but also what others expect of me. by avoiding pressure from others and not expecting to much myself but without considering that a failure, or by not blaming myself if things don't work out, in other words, avoiding things that would lower my self confidence, may be a way to avoid depression.
i have never tried NaNoWriMo, but if i did, i'd look at my situation and realize that i would not get much done, but for me that would not be a failure, because i wouldn't even go in with the expectation that i should be able to change that. on other words, i would not even have the hope that it would go well. instead it would be the realization that without participating i'd write nothing. by participating i'd write something, and so i may consider that a (small) success.
While I empathize with your situation-- be careful not to discourage others. The only two fully completed novellas were because of this month and I'm very proud of them.
I'm much more annoyed I haven't been able to replicate this outside of the contest.
I want to be clear, I am not trying to discourage others - however, I did try NaNoWriMo because of an aura of "everyone should do this, it's great" from people around me, so I am more just making the gentle point that people shouldn't feel that they "have" to do NaNo, or that there's anything wrong with them if they try and fail.
If it does work for you, that is, of course, great.
Indeed, NaNoWriMo does - by the very nature of its focus on "pushing yourself to succeed" and positivity in challenge - make it hard to talk about not succeeding. (And I am pretty sure that attitude didn't help my own interactions with it.)
It's also, you have to make an artistic sacrifice when you're doing it. You're writing a first draft of a novel, but it's not meant to be a good first draft, it can have plotholes and characters who learn nothing and unintentional red herrings and all sorts of other stuff that drives readers up the wall.
My book, I got to the word count but the characters hadn't done a quarter of what they were supposed to over the plot, it was a book with an extended beginning, a little bit of middle, no resolution or ending. So I learned a lot about myself! But if I was trying to actually make a worthwhile narrative, well, I need to consider how much reasonably fits in 50,000 words and how many books do I need to tell the bigger story.
I attempted it twice in consecutive years about a decade and a half ago, and not only failed to complete anything, but was also driven into a worse depression because of it. I had to avoid people talking about it in November for years afterwards or I'd start to relapse, too.