So now 4 days in and 2 days into taking 2 tablets per day the side effects have hit. I'm now sitting on a ferry waiting to disembark and start driving up through The Netherlands, Germany, Norway, Sweden and Denmark over the next thee weeks.... After a night on the ferry with completely liquid diarrhoea and facing several days in the car I didn't take the dose this morning. It's going to need to be a very careful diet and start again when I get home.
I think in your circumstances, I'd go back to basics, stop the metformin now, eat as low carb as you can, if you have a meter to check your blood glucose, please do so, so that you can see the effects of what you eat on your sugars, it can sometimes be surprising!
Sometimes if you take metformin, yet carry on eating the same fairly high carb diet, it has these undesirable effects. Don't ruin your holiday. Eat what you want but don't go mad.......
When you return, explain the circumstances to the prescriber and ask for the prescription to be changed to a slow release metformin, this certainly helps most people with any gastric issues.