LOL at "dreadmill"! May I steal that expression? :-)
I just took a cruise in May, so I sympathize. Two things kept the cruise weight off me this time: (1) I was super-careful with my buffet portions because I was embarrassed to see so much food going to waste and didn't want to contribute to the "ugly American" stereotype, and (2) my friend and I volunteered as tour escorts on as many of the shore excursions as we could, so we did a lot of walking. But yeah -- cruise ships are giant food pits!!! Best of luck to you, and congratulations on getting back on track!