During each of the 4 cruises we have taken (all
DCL) I was continually motion sick, and then after the cruise spent the next few days "land sick" where I still felt the former ship motion and sometimes had trouble walking properly as a result. The only question was how severe the symptoms were and how much they interfered with activities. For the most part, with the below "cocktail" I was functional (if a bit drowsy at times) but still aware of the motion sickness -- but it was mostly kept at a level of "annoying".
I use a combination of:
- Dramamine Less Drowsy (meclizine), started 2 or 3 days before cruise and taken daily through 2 or 3 days after end of cruise
- Sea Bands, worn 24/7
- Dramamine/Gravol ginger capsules/tablets (a fixed known pharmaceutical grade dose of ginger), daily not exceeding instructions
- ginger ale (prefer Canada Dry brand, but will take what I can get)
- ginger snaps (Shasha brand is very good, and for me safe for my food allergies)
Backup is Dramamine/Gravol the original version, but it makes me really sleepy, so is only used if I can no longer tolerate the residual motion sickness symptoms, or e.g. am actually throwing up. I also have Benadryl, but try to hold it in reserve for allergies.
As an aside, I also use the above for nausea due to migraine and medication. They work better for those reasons than for motion sickness, for me
One interesting thing I did discover accidently one night when the seas were rough: the angle you lay on the bed can make a difference. So, head facing foward, head facing backward. Lying perpendicular (across) on the bed, or at an angle. That night I had laid down across the bed instead of in line with it. After a while when I got up and moved into the "proper" orientation suddenly the motion sickness got much worse. I spent the rest of the night sleeping laying across the bed

Practically, if you normaly are sleeping in the bed, try the sofabed out and see if that makes a difference -- you lay perpendicular to how you lay in the bed. Our sofa bed was occupied so I just lad wonky on the bed (which was all mine anyway).
SW