Terrified, really? Terrified. Terrified? It's 3 weeks on an island with the love of your life, not 6 months in poundmeintheass prison.
With these types of questions, I always defer to a killer quote from Wendler:
"Just train and then take the vacation. When you get back, start training again.
If one trains hard in the weight room, uses AirDyne every day, jumps 3-4 days/week, runs hills/Prowler 3 days week - these "life" vacations are deloads that won't matter. You come back home and you can immediately jump back on the horse.
The problem is that people rarely take advantage of the time they have at home. Anything less than 100% compliance with ATTENDANCE and EFFORT is not conducive to reaching your goals.
It takes NO TALENT and your GENETICS don't matter in regard to attendance and effort. Just like it takes NO TALENT/GENETICS to be in-shape and to make yourself stronger than you were before.
So the problem is never about the deload or the vacation.
When I'm on vacation, I'M ON VACATION. I've made the 'gotta find a place to train' mistake way to many times."