I think our ability to produce creative content is in a state of fluctuation by default; meaning that you'll have days where everything just seems to go smoothly without any effort, and other days where you can try three times as hard and still feel like you're getting nowhere. It's something to expect and keep in mind, as people are dynamic and so are our moods and abilities. That by itself isn't alarming, and something we should accept and work through. The important thing isn't that all your content is as good or better than the previous, it's about staying in motion and continuing to practice.
I also believe that our perspective is by default skewed and biased. When I was in my mid-teens, I drew things I felt were awful and unskilled, as if I unlearned everything I learned. A few years later, I was able to look at my drawings and suddenly they looked totally different to me. As I got older and progressed with my skills, I was able to stop judging myself so harshly and appreciate the things I did well. Sometimes, it's a matter of being too harsh and criticizing yourself without praising the things you did well. So maybe with your next sessions, instead of comparing it to your previous works and judging the things you didn't do so well, try to look at the work as standalone and allow some praise towards the things you did do well!
That said, breaks are important! Just like how atheletes need to take breaks to allow their muscles to heal and grow, we need to allow ourselves some days off where we try to process what we learned and just rest. It's good to have a daily routine, but if it comes at the expense of your progress, consider adjusting your schedule so that you can take a breather between sessions.
