Lymommy, I'm hitting my 8th cruise this time around and I've been on some gnarly swells, one hurricane almost ruined our stop in Bermuda! Anyhoo, my cure? It's STAY OUT OF THE ROOM. Yup,
I would suggest going dancing or keeping near some fresh air, but in the room it's like all you think about is the feeling of rocking and rolling. On the dance floor you just wobble the electric slide in the direction of the rolling, and it's pretty fun! The kids like to hit the "wave" pool when it's rocky like that.
Hopefully you are in a middle and/or lower cabin because that can help when you're ready for bed. I can get car sick, and boat sick (Catalina Ca. boats can really rock!) but rarely get ship sick. Sometimes I feel it when lying in bed (insomnia) and I picture myself being rocked to sleep by a giant mom (LOL).
I see people with patches and pressure wrist bands (I tried when I was deathly preggers...didn't help me), and they swear by them, but are never without so who knows if it is working. Ginger, granny smith apples, keep your eye on the horizon, Dramamine, Benadryl (both of which slow down your body to trick it into not caring about the motion, unless you are like me and my kids and it can hype you up with the antihistamines), and I actually have a prescription for something right now from a stint with strep throat, and it made me sleepy and worked.
Oh, my girls never get sick (knock on wood), this will be their 4th cruise, ages 4 and 7. Syd gets car sick, but not ship sick. A little boat sick on Alaska whale watching boat, but we took her out in the air to look at a stable horizon and she was good.