Just keep hanging in there!
I have been at a stand-still with my weight loss for a long time now - I got down to 7 lbs from my goal weight (after not losing a pound for almost 6 months) and I, too, went on a cruise and gained 7 lbs. I don't regret the food I ate there, it was Italy & Greece and I loved every bite - but it was a set-back.
I'd only lost 4 of the 7 lbs I gained and then went home to the midwest for a week and gained 3. So, I am back to exactly the weight I was on Nov 5 of last year! It bums me out, but it also bolsters me because I am still working out 4-5x per week, I am still eating well the majority of the time and I haven't slipped back. That's a huge victory for me.
I think you have to not be so hard on yourself. Every "normal weight" person I know has gained weight on a vacation here and there. You haven't blown it, you just had a great vacation and now it's back to reality.