Let me give you an uncomfortable truth: writers are planners!
Either we are writing, writing to write or thinking of writing! There is no off switch for it! The only thing you can do is catch these ideas when they come and how they come to you.
You are a writer–time is a tool and an obstacle. Once you confront this, you can do anything! You will be able to look at the work you have in front of you (and hidden in your own head) an begin to designate space for it! From that space, you can make outlines and deadlines!
You are the master of your time! Don’t forget that. You pen is yours, and so is your willing talent. Harness both.