The pedialyte was an excellent idea!
You can also see if bland food will help your pet 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.
The fiber in the rice will help bind up fluids.
Its likely though that you are seeing the results of an intestinal infection common in pups such as worms, coccidia, or giardia. The last two are protozoan type bacteria that cause diarrhea in pups.
Usually the vet will check the stool sample and prescribe meds. I find using the pedialyte and the bland diet along with the meds helps the pup out a lot and that you can slowly get the puppy back on a regular food diet as it feels better.
I would not use any over the counter anti diarrhea medication as if its a bacterial infection you do not want her bowels to slow that much until the bacteria is treated.
You can though see if the intestinal soothing meds such as Pepcid or Tagamet or Zantac will help.
Be sure to tell the vet when you see them if you use any of these.
You can read about dose amounts (and cautions) scrolling down on the pages here
I commonly use one of these with pups who have digestive upset and that too helps them feel better.
What happens is the pup is stressed going into a new home, just from the changes in its life, and where it might have been handling a low grade infection easily it becomes sick in the new home as its immune system isn't functioning as well as it might be due to stress.
Hope this helps you!