Wow, what a great question.
There are four players when it comes to diabetes: diet, exercise, managing stress, and getting adequate sleep. To that I'd add getting enough plant fiber in our diet to support and improve the diversity of our gut flora.
I live in the US so have am unfamiliar with Majorca. Now that I've Googled it, I'd like to join you.
The weather there is similar to what we have here in August - (warm during the day, cooler in the early morning hours) - so you might be able to get some good walks and swims in during the day. It certainly would bring your stress levels down and allow you to rest and relax.
As for the food and beverages, perhaps you could eat low carb for breakfast, perhaps lunch too, then eat whatever you want in the evening. I have to say though, I'd be surprised if they didn't have lots of wonderful low carb food choices for each meal. I'm assuming fine dining is available for all meals.
I encourage you to stay away from the sugary mixed drinks and beers which likely will make you feel absolutely awful the next day. Red wine and spirits are both fine on low carb.
Listening to you, it sounds like your body is converting over from carb burning to fat burning (ketosis). It's a miserable place to be - (low energy and mood; irritable) - often takes two or more weeks without cheating, but once the conversion is complete, you'll have lots of energy, and your mood likely will improve too.
As for your 4 day time away, the worst that could happen is that you'd just need to re-start the conversion process again when you get back. But you've almost done it once, so you'll get there next time.
When you get back, I'd really like to hear how it went. Sounds lovely.
