Honestly one of the most important things I can say I’ve learned as an artist is that if you feel like you’re really stagnating, that probably means you’re seeing problems in your work that you have never been able to see before, but you haven’t figured out how to fix them yet.
You’re not really stagnating
You’re understanding of drawing has moved beyond your current execution.
Once you have finished processing the problems you’re suddenly seeing, you’re likely to correct them and suddenly make a huge breakthrough in your drawing.
Don’t push yourself, either. Sometimes you have to remove yourself from a problem temporarily to solve it, just don’t give up drawing altogether.
TL;DR feeling like your drawing is stagnating/getting worse means your eye is improving, and your hands are likely to catch up soon.