Do you ever really get used to it?
I was on a cross channel ferry from Roscoff to Plymouth during that one. All was calm for the first hour, then it was a few hours of total bedlam. Decided to stay in our cabin as it was pretty much impossible to stay on your feet as the ship was battered. We could hear car alarms going off & the whole ship shuddered as the waves hit. Eventually it calmed down for the last 40mins before arriving in Plymouth.
When we went back to the upper decks, it was like a scene from the aftermath of a huge fight. Anything that was not fixed down was scattered, mess evertwhere. Still loads of people sitting on the floor looking shocked whilst holding sick bags. The smell was awful.
I had to just park up for a while once I got away from the port to try to give my head a chance to clear as still had the motion sensation going on.