We are on the Celebrity Zenith (Your itinerary reversed) on 12-22. I have been watching the prices of both ships since April. We have an outside guarantee and paid $1735 p.p.
That was at the lowest rate I saw all summer less a $250 coupon from Celebrity. The Zenith is nearly sold out at this time.
I looked on the internet today and found your cruise, on the Dream, in an outside cabin at a rate of $1689. That is not a bad rate considering it is Xmas, New Years, Hannukah, etc. (I am not however, partial to the Norwegian Dream.)
This was a category "G" at Cruise Professionals. I have never used them and don't recommend them in any way. It was the cheapest rate I found, however.