It totally could be burn out. Like, what's more burn out-y than going through the motions but not feeling it?
At any rate, I'd start by evaluating my goals, if I was you! If art feels like a waste, what feels productive? How much pressure are you putting on yourself toward being productive? What do you want out of your art?
I don't remember ever thinking of my art as a waste, but I do think I had a big gap in pursuing art at a time when I have a lot of stress and anxiety about my future. I can totally see someone in a similar pickle, stressed about being "on track" towards some kind of future, feeling negatively about time spent on normally pleasant things that don't push you toward the imaginary goal.
I don't think creative time is ever a waste, regardless of if one has professional goals, or is having fun. But it is okay to put that stuff away if it's not feeling good. You can always pick it up down to road if you decide you miss it.