Ok so you are on a getaway. whether its another county, or country the change in water hardness can really make a difference. We used to own a caravan and 9/10 everyone who went could not go for days.
As long as you are eating ok and drinking fluids its nothing to worry about. you are doing the right thing with fluids and fruit helps.
Should you not go within by 5 days, you can go to the pharmacy and get things that can help over the counter. You do not need a gp, just a pharmacist will do. And anxiety is a big cause as well.