You might want to have a fresh stool sample checked to make sure she didn't pick up an infection like giardia or coccidia while visiting away from home.
You can try some home remedies. An over the counter med you might use would be Pepcid or Tagamet.
Be sure to tell the vet if you see them if you use either of these.
You can read about dose amounts (and cautions) scrolling down on the pages here
http://www.petplace.com/drug-library/cimetidine-hcl-tagamet/page1.aspx
http://www.petplace.com/drug-library/famotidine-pepcid/page1.aspx
You can also see if bland food will help your dog feel better.
I would suggest trying boiled chicken meat or hamburger with the fat drained off, mixed with really well cooked rice in a ratio of 1/3 meat to 2/3 rice to see if that works. It’s not a balanced diet but OK to use for a few meals while working on controlling digestive upset.
If it doesn't work another thought is an x-ray as she could have eaten a small toy belonging to the kids that isn't passing through her properly.
Hope this helps you!
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