What do you do when you don't have any plans and your laptop is calling you?
I know, I know; leave the house, go for a walk. But how can that compete with the allure of PRODUCTIVITY! PROGRESS! GETTING THINGS DONE!
What are your long-term goals beyond releasing the app?
Do you want to have many people using it? Will they pay? How do you want to market the app? Do you want to hire or join a dev team? Do you want to manage a dev team?
Technical sales, coding for a team (instead of yourself) and management are all learnable skills, but they don't seem as time-critical to an engineer so they seem like they can be pushed off.
However, you need to start somewhere, and if you focus on shipping something out the door then you'll never get off that near-term treadmill. So, read up on those, listen to podcasts or videos on the topic, etc.
Or, are you working on the weekend on your off-time to develop software for your employer? In which case, I'm sure your employer is happy with your free donation of part of your life, and won't do hardly anything in return.
Or, are you worried that co-workers are also working on the weekend and you'll lose your job if you don't keep up with them? In which case, you're in a race to the bottom. Start learning about labor-management relations from a pro-labor perspective.
I actually have ended up thinking about my marketing efforts and watching videos about that instead of tinkering with the app (or other appealing ideas that inevitably emerge during down time).
Do you have early customers/friendly users? Have you done any UI testing? Paper prototypes? Do you have a clear idea of your users' goals?
While dated, read "The Design of Everyday Things" and "The Inmates Are Running the Asylum".
If you don't have users even to the level of being able to provide early feedback for non-functional UI designs, then you are probably doing too much coding and not enough user testing.
(That's easy for me to say, but there's a decent chance I'm wrong.)
Also, generally, don’t forget to take vacation time. Especially solo trips!
But I actually have the opposite problem, I struggle to do any sort of computing work, even leisure projects, after my work day is over. For me, work has ruined the hobbyist aspect of computing.
Sometimes you need to get yourself in the mentality of the employee who knows that they’re just selling precious life to the employer. I absolutely don’t stay past 4:59 and usually work something closer to a 9:30 to 4 day (nobody really notices).
On the bright side, at least you’re motivated by your work.