Honestly, for me, it is a mixed bag from everything everyone in this thread had said, plus a bit of psychology on top.
First off, i am not an shining exemple, because I've haven't uploaded any new chapters in months( though i am still writing). And second: i am no psychologist or psychiatrist, but: I've read and learned a lot on the subject, at least to try and understand myself better. Those are ways that help me keep writing consistently, if they can help you then go for it, otherwise feel free to ignore.
My observations are:
- pacing and schedule: helps a lot for motivation and not burning yourself out. What also helps is dedicating a set time before hand where you know you'll have time to write, this gives structures and helps form habits, which over time, will help you brain figure out that "Ah! This is the time to be creative, let's fuc**** go!".
But once again, i am no psychology major or anything, it works for me, might not for you.
While i am speaking about scheduling and pacing, if you know about the pomodoro technique, it helps, if not go look it up, it boils down to working in series short sequences spaced with breaks (it can be 10 min like it can be half an hour or even seen hour), with the goal of increasing the time you work each time. The main objective is to work as much as you are able to focus, meaning that when you feel your focus dropping, you push a little bit more, but not more then a minutes or two.
- learning to get bored / let your brain rest : this also help with motivation and creativity. Things like using your phone while on the toilet, reading or watching something while you eat, or listening to a podcast while doing something else like driving: all these types of things will take up the time your brain needs to rest and recover from your prior activities. The brain craves variety as much as it craves stimulus, so having moments where you are actively resting/doing nothing and moments you are actively doing something with intent helps both recover faster and better from mental fatigue but also be more focused and motivated in what your are doing. Remember, the brain hates boredom, but can't endure it as well as you can, meaning that you can wait it out until you feel motivated to write.
- Managing expectation: with my case being similar to yours, i really struggled with wanting to write and being unable to: when i started going to my social worker training in September, it was really exhausting and i needed (and still need) like two to three hours each day afterwards to recover, letting me only two hours to do my homework, cook for the next day and clean up before going to bed. What really helped me then is accepting that i won't be able to write during week days, it pulled a weight of my chest like you wouldn't believe. Between the stress of returning to school at nearly thirty, having to slow down/stop writing when it started as both a passion and a therapeutic project, it had hit me hard. But accepting that i can't and shouldn't write when i don't have time to do it helped a lot. Especially when i scheduled my writing session on the week end, made me really anticipate and look forward to the times I freed expressedly for that.
- last but not least: the weight of what you want to do and why do you write?
No need for a grand reason or whatever, just: why do you want to write?
Remembering the whys is what helped me keep writing.
Currently, my life is split between: school, school related activities, needing to take an hour long walk at least 3 time a week, speaking with my friends, writing and sleep+eating.
Each are extremely important to me, some more then others: i need my schooling to finally get a degree, i need to have my walks for my mental health, same goes with my writings and speaking with my friends in top of the other reasons.
And i cannot, under any circumstances, cut down on sleep and food, I've been there and done that, and i absolutely refuse to go down that miserable path again.
But between each of those are cracks and gaps where my bad habits sneak into, transforming a 15 minutes meal break into a thirty to an hour doom scrolling, toilet break turns into more doom scrolling, getting back ready to sleep only to see a thirst trap on my feed making me hor**, etc...
This is the worst time sink i have in my life, and i am still trying my best to unscrew it and free myself from them. But on the days where i am about to do so? I find much more free time to do whatever the hell i want.
So yeah, good luck with that as well.
TLDR:
-make a schedule for times reserved just for writing,
-pace yourself so you don't burn your creativity and motivation,
-maybe use the pomodoro technique,
-learn to get bored by not using your phone where you shouldn't, aka stop filling your time by being "productive" (doing two things at the same time)
-take true and intentional breaks where you actively rest,
-accept that you cannot write as much as before,
-weight the things you do in your life to decide what's important to you,
-be careful of addiction and bad habits by planning your days around them by generating options of the things you can do ( good and bad) and what want to do and play out the consequences of each choice in your head.
-mind any gap or crack in your schedule and stop them from swelling into hours long "waste of times".
Good luck. Hope i could have been of any help.