“Over your head” is a slang phrase, referring to being in water that is over your head, too deep to stand, and therefore too much to handle.
But for growth, that’s the place to be.
Whatever you’re doing in your life right now, if it’s become a routine, it’s time to move on to something new and scary.
Abraham Maslow wrote, “Life is an ongoing process of choosing between safety (out of fear and need for defense) and risk (for the sake of progress and growth): Make the growth choice a dozen times a day.”
Whatever scares you, go do it.