Dramamine and ginger is great. Also, if you drink and know the seas are going to be rocky, hold off and don’t because it doesn’t help.
Ondansetron while a great drug for general nausea and vomiting has been studied extensively with motion sickness and does very little if anything to help. Take it from a retired pharmacist. Different receptors in the brain. I knew one person on a cruise who swore it helped but I’m pretty sure it was probably just plecebo effect.
Day after I can’t thing of anything except rest and plenty of fluids.