Re: 1st boating experience...Did not see the FUN in boating
Sea sickness is a funny thing. Different circumstances can set it off and once it gets going it can be real hard to shake. I was out the other night doing some racing on a guy's Beneteau sailboat. Real purpose-built high performance machine. What with all the lines, winches, blocks, and other rigging I was learning to use I found myself getting queasy in the two foot chop we were in. I haven't been even slightly sick in the last two decades of powerboating. I think the problem stemmed from concentrating (and looking) by turns at the deck and up the mast as opposed to manning the helm and staring at the horizon, or at least up off the boat. You may have been in that situation as the sales guy was showing you stuff and you were trying to absorb it all rather than get a feel for the boat itself.
I would concur that it's worth trying different hull types and sizes as well as engines. There might just have been something about the unique combination of that boat's ride, feel, and sound that set you off. And while bigger, heavier boats have a more forgiving ride in terms of pounding, the slower, smoother rhythmn of the bigger ride may make the physical symptoms worse.
Good luck and I hope you find something you can not only live with, but come to love like the rest of us nutjobs do!