How wonderful that you will be going on a cruise! Do NOT take the the less drowsy dramamine! It still knocked me out for 3 days of vacation. The motion sickness bands worked like a charm. If I find myself getting motion sick when I don't have them, I also have my husband press the points himself until I feel better.
Here's a link to where you an order them online if you can't find them at the store. I bet Walgreens or any other drug store would have them though, and they might even be cheaper.
http://www.biobands.com/
Also, I normally get motion sickness but have never had motion sickness on a cruise ship because the ship is so large it was hard for me to tell it was moving. You might not have as many problems on it as you do a small boat or plane.
HAVE A GREAT TIME!