Dreams are meant to be big. Anything less and it's probably just an errand.
But, a big dream can often overwhelm and leave us unable to act. The sheer size of a great dream can make us feel like we'll never accomplish all we hope to in our lifetime.
Perhaps our dream is so hauntingly big because it includes a lot of stuff that we don't need. Just as the sculptor removes marble until the image is perfectly revealed, so too must we remove the things that aren't essential to our dream.
Then, once we get a clearer picture of our masterpiece of a dream, we can get to work.