Book a cabin as low down as you can. The yaw of a ship is greater in outside cabins, so get one that is mid ship, lower deck, and inside rather than an outside cabin with a porthole.
The worst moments of my life, as a non swimmer with toddler in tow was in that outside cabin watching the waves submerge my porthole! Add sea sickness, and a toddler impervious to any dangers or worries made it the worst few hours of my life. I dare not sleep, and was thrown out of my upper bunk several times, ended up sleeping in a nasty draught on the floor,
Havnt been on a ship since! Though I would still go if a trip arose. Hasn't put me off realy, I think it was the responsibility for a little life, aswell as my own that gave me the heebies.
I could have enjoyed the trip but for that.
I'd add some mouthwash and wet wipes just in case you need to clean up, but I reckon you'll be fine. I used to love rough channel crossings on deck up the front as far as I could get, watching every wave, and being covered in sea spray, while everyone else was being poorly!. It's quite exhilarating.