Comics is a marathon, not a sprint
As a depressed younger artist, my storytelling sometimes suffered. I just couldn't conjure up the feelings & images that the story needed. Over time I found some strategies for staying professional even when I wasn't feeling it.
1. When too down to do justice to the stuff that needs energy, do other stuff. Taxes, erasing, booking travel, laundry, scanning.
2 Break down the job you can't handle into smaller jobs you can. Is the thought of a whole book too much? Thumbnail a page or a scene. Design a character. Ink backgrounds.
3. Bring in a helper. A collaborator or assistant doesn't just lighten the load. Their enthusiasm can be contagious. Increased momentum helps, too.
4. Learn to recognize your green kryptonite. For me, it was drawing tight pencils for someone else to ink. I was working with great people, but I just hated drawing a pic for someone else to redraw in their own line.
5. Embrace tools that make your job easier. I used to be anti-photoref. I drew a perspective grid for every gun or vehicle and constructed it anew. Using photoref and 3d models meant I could save all that time and energy, and use it for making better storytelling choices. Your energy is finite. Spend it wisely.
6. Understand the emotional goals for a page. "I need reader to feel scared along with Jimmy" vs "I need the reader to laugh at him being scared." I'll write those goals on a post-it as a way to remind myself what I'm aiming for. This helps when I have to steer towards a feeling via pure technique.
7. Improving my technical chops over the years helped a lot with this. When basic drawing was no longer a hurdle, I had more time and energy to conjure up feelings.
I recognize there's some danger in talking about this stuff. It's easy to believe that the only acceptable public face is that we're always excited, always operating at 100%.
Every artist I've ever spoken to has had to deal with this. A comics career is a marathon, not a sprint. We all have our own ways to keep going.