Good Morning and welcome! I am Dr. Loretta, a licensed veterinarian and I am happy to answer your question.
I am so sorry that your gal is not feeling well. The excitement of this change in environment and other dogs could stress her out enough to make her not feel well. Also, she may have ingested something odd during this trip to cause a digestive disturbance. With stress, young puppies can suffer form hypoglycemia so the first thing you should do is give her a teaspoon of Karo Syrup that will give her a dose of sugar. Do this every 6 hrs. Next, the best thing you can do is to follow these instructions:
Fast her for 12-24 hrs which she is doing herself to allow the digestive tract to calm down and heal.
Give Pepcid AC or Famotidine at 0.5 mg per pound every 8 hrs. That can be purchased over the counter at the pharmacy.
Give only small amounts of water during the fast or ice cubes and give a few teaspoons of Pedialyte every 4-6 hrs to be sure she remains hydrated.
After the fast, feed rice and boiled chicken (2/1)
If she is feeling better, then wean her back onto regular food. If the depression persists, take your gal to your vet for an exam and lab work to determine the cause for this. This is extremely important since this can cause dehydration or other more serious concerns such as an infection.
Does that make sense to you?
Please let me know if you have ANY other questions. My goal is to give you 100% satisfaction and if you are not yet satisfied, please REPLY so I can clarify for you.
Sincerely, ***** *****