I feel like the obvious answer is pacing/scheduling/checkpoints, but for me I don't feel like I've developed that competence yet.
I get so excited making, planning or thinking about something, and I'll keep demanding of myself to do something when I'm out of energy.
What are some things you may have learned to help you start planning out a solo project while still satisfying you with progress and leaving yourself time to decompress?
What I did was I made myself pick 2 days in the week to work on this game, those 2 days I commit myself to game development in any way imaginable. At first this promise I made to myself didn't really work because my mind easily drifted off towards assets for my game and how to implement them any moment of the day. So then I started using a notetaking app on my phone and allowed myself to jot down any idea I had during the day and not think about them further. At the end of the week I would organize these notes.
I still got fatigue from all these ideas I kept having so I had to go further.
So then I made a place away from home to work on the game and made myself promise to only work on the game at this specific place, this seemed to really help me. Maybe it helped because I now associate this other place with the game so that I could return home to relax instead of "think about work"
I hope that this might help you in any way, don't give up and try to organize your thoughts! Looking for help is a very courageous decision, you don't have to do it alone :)
Personally I believe committing to a project and sticking through with it is the hardest part about game dev, that being said small, bite-sized goals help me the most; for instance I try to break down nearly everything into steps and checklists. Currently I'm working on my main menu for my game, I've got it broken down into many steps such as: main menu title art (this is broken down further into the animation, the actual art, the implementation into the engine, I could go on but hopefully you get the point). Make it feel like you're making progress!
Also, scope of your game: keep it small!! Don't get stuck just adding mechanics and then the scope gets HUGE cuz then you'll never finish and you'll just get discouraged.
Yavga has a good point with separating work and home as well. I can't add much to that point as I'm (almost) always thinking about my game / planning, whilst at my real-person job anyway.
And if you truly don't feel like working on your game, take a break! Nothing wrong with that.
I would say have days or weekends where you completely don't think about game dev or whatever it is you are trying to accomplish. It sounds like such a simple idea, but it seems to work for me. When you can fully relax or do something enjoyable without having that guilty burden looming over your head of "Oh I should be working on something", it allows you to fully enjoy your leisure time while also kind of recharging your batteries for the thing you want to focus on.
