I resonate with that idea so much! Especially after listening to Allen Watts. I like to say (or parrot people like him?) that our external world is a reflection of our inner world. We are OUR universe, certainly. Like the concept of karma-- everything you do comes back to you somehow, and the quality of what you do determines the quality of what gets reflected back.
In college I used to hate the term "relationship with God" because it seemed so vague. (God was a vague concept, and its hard to have a relationship with a vague concept) But nowadays that phrase means something more like "relationship to yourself and the universe" which are made up of tangible things that you can see and do stuff about.
"I am the universe" to me means that I am the source of my universe, and if something in it needs changing, then that must mean there's something about me I could change to influence it...
Thanks for letting me share my stream-of-consciousness nerd thoughts :)