💩 question for you mommies out there who have kids who are at least 21 months

My daughter, Phoenix, has been having awful diarrhea for I'd say about a week or so now. We're on vacation and staying at my in-laws. Her diet hasn't changed much compared to what we have at home. She is at that fun stage where she doesn't want to eat. She'll "snack" on small stuff like peanut butter and jelly sandwiches and mac n' cheese but she won't usually eat what we have as full meals. She did that even back at our house but she never had diarrhea. Hers is basically just liquid. It's gross and it's very, very watery. Its accompanied by a rash (which is almost gone now) and she isn't fussy about it. I don't notice until I see her pants are wet and it's leaked out of her diaper.

My question is what can I give her or what can I do to help get rid of her diarrhea? They usually don't "recommend" most types of OTC medication until about 2 years old and I think the age for anti diarrheal medicine is 6 years I think 🤔 She has an appointment coming up with her doctor but I've heard some good insight on some remedies on other things from other moms before and I was curious as to what some of y'all have used and recommend for young children and this problem.