At the end of the school year, I vowed that I'd never be so disorganized in my teaching ever again. I spent the entire summer planning my lessons for the next year. I was assigned 8th grade math again and also an Algebra class. By the time school started, I could tell you exactly what I'd be doing during either class any day of the year.
It was my worst year of teaching. I had spent so much time focusing on the content that I had totally forgotten about the students. And I put so much effort into the plans that I was resistant to altering them. My students and I were all miserable.
I share this story with the teachers I work with as a cautionary tale. It's tempting to want to be totally prepared for every lesson. Unfortunately, it's impossible. It's better to have a lesson prototype in mind that can be altered in response to feedback from students. We use a version of this One-Sentence Lesson Plan as a framework for our prototypes for designing math adventures. The incompleteness leaves room for student-voice and student-choice during the lesson experiment.
So, instead of spending the summer planning out every detail of the coming school year, please keep it simple and give yourself some time to recreate and restore. Maybe you could explore some new places. This will hopefully re-energize you and allow you to be more responsive to the students in your classes.