You poor thing. I understand exactly how you feel. My emet may or may not have developed or at least increased from my brother being s* on a plane.
And I just had a nine hour flight, also moving countries.
May I suggest anti-nausea drugs?
They don't have the potential side-effects of sedatives (my mum recons sometimes they make you feel a bit gross when you wake up)
Plus they tend to make you a bit drowsy and relaxed, all the while reducing the chance that you will be s*
I made it on one xanax

Good luck in Spain, and try to enjoy it
xx