I get motion sickness on pretty much any mode of transport. Years ago I got sea sick on a smaller Carnival ship, also out of Mobile. We were sailing through remnants of a tropical storm so it was quite rough. My cabin was down low, but at the front, and I was miserable that first night. Going up to dinner and on deck helped me but I also took non drowsy Dramamine. I plan on bringing Bonine as a preventative on my upcoming cruise, but honestly, that was the only cruise out of many that I have ever been unwell on.
Its not easy to do based on cabin and bed configuration, but I have also found that different sleeping directions help me too. Sometimes I need to sleep across - like pointing port to starboard, and other times I need to be sleeping bow to stern. I am weird, but it helped me.
I get sicker in cars and planes than ships for some reason.
I hope you are able to find a good solution!