This is a difficult one. It's really horses for courses. Both OH and I prefered the longer ferry trip to and from France (Brittany Ferries). We both regarded it as part of our holiday, but our approach to a stormy crossing was poles apart. His default position was a good blow-out in the resturant, a couple of stiff brandies and out like a light , waking up bright -eyed and bushy tailed for the ongoing journey. Me.... it was get my head down in the cabin and go with the rock and roll. Hopefully it would lull me off to sleep.
If you're going soon, the crossing should be smooth, so enjoy.
And a stay in Brittany will make it all worth while.
Oh, just remembered, D2 hated ferries so I shoved a few Kalms into her before we embarked. Never was in the running for the "Mummy of the Year" award, but you could try that.