I second what Keebablue said. Switch things up and find something you love to do.
On the subject of motivation (found this online but it says it better than I can).
It’s a fickle and unreliable little state that isn’t worth your time.
Better to cultivate discipline than to rely on motivation.
Force yourself to do things, to get out of bed, to go the gym, to work harder and smarter; force yourself to do stuff when you don’t feel like doing anything.
Motivation is fleeting, and it’s easy to rely on because it requires no concentrated effort to get. Motivation comes to you, you don’t even have to chase after it.
Discipline is reliable; motivation is momentary.
The real question isn’t how to keep yourself motivated, it’s how to train yourself to work without it.
Hope that helps and good luck