Thanks for the additional information. Since she came from a pet store environment, it is likely she has kennel cough. Puppies from pet stores and puppy mills often are exposed to kennel cough. Given her size and age, I'd have her seen as soon as possible by your own vet. Often your vet will go ahead and prescribe an antibiotic to tiny young pups to help prevent a secondary bacterial infection from setting in. Kennel cough usually lasts abotu 3 weeks or so if no secondary infections is present. There is really no way of determining how long she has had it either. Read more on kennel cough here:
Now smaller breeds also are prone to reverse sneezing and collapsing trachea which can also sound similar. You can read about these here:
In addition, I'd ask your vet to check for a liver shunt. Many teacup breeds are that tiny due to having a medical issue that stunts their growth. This is not unusual in pet store pups as they are usually bought from large scale breeder or puppy mills. Pet store will tell you one thing but reputable breeders do not sell to pet stores. Your contract should have a clause in it about congenital defects being grounds for a refund but typically a contract will have a set number of days in which you must find this "defect" and often it is 3 business days. If you are still in NY, here is a site that should be helpful to you.
Here are also some sites that will give you some background on pet store puppies.
I don't mean to be the bearer of possible bad news, but better to find out immediately if there is a health issue with her instead of a year down the road when you might not have any legal recourse. I really hope she just has a bit of kennel cough but get her in to your vet and have her checked over.
The blood in the stool is probably the result of worms or a protozoan infections (coccidia and giardia). Your vet can check for that as well. Be sure he checks for coccidia and giardia as those are common in pet store pups as well. All of these can lead to blood in the stool.
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