Gosh, I really struggled with this problem for a long time. The worst part was that I felt so alone in it. Everyone else seemed to find time and energy to practice, no problem.
What was wrong with me?
Turns out: Nothing.
I had just grown up, and grown-up things were happening with me, and I had to deal with grown-up things. That really eats into your practice time.
I have been guiding my adult students through this issue, and now I see it finally asked about in my comment section. I hope that what I have to say about it at least helps you all not feel so alone. We're all in this together. :)