I will never be able to share the majority of the lessons and resources I've used in my classroom over the years.
Why? I didn't create most of them. It's a cliché at this point, but nevertheless true: effective teachers beg, borrow and steal.
I usually found that while no single resource (textbook, teacher resource book, online lesson idea, district curriculum guide, etc) met the needs of my students for a given lesson, there was almost always enough to create a working sketch. After that, I could simply fill in the details.
Sometimes I just needed practice problems to supplement a step-by-step example I had created, or a word problem to make a real-world connection with a challenging concept. Sometimes I just needed to add white space for students to show work or add a helpful graphic organizer.
A lot of the time, I simply needed to incorporate my hilarious sense of humor into an otherwise dull topic, or make someone else's work fit into a lab, project or other student-led activity.
I've never felt guilty about this, and neither should you. Everything you want to do has been done before, if not exactly than in bits and pieces spread across the education ether. Being able to synthesize disparate resources into something that will help your students is a skill you need to hone.
If you spend your days and nights trying to be the world's most original teacher, you'll very quickly find yourself becoming the world's most frustrated.