Try boiling some chicken, chop it up, mix it with the dry food and pour water or the chicken water over it. She needs to stay hydrated. Maybe a little boiled white rice mixed in too.
Don’t keep adding all kinds of stuff or supplements, it will only make her more nauseous.
Keep it plain and simple, only give what the vet has ordered. Don’t leave food down, but offer her small meals with water added frequently.
This dog has been through a lot, heartworm treatment is hard, she still has a way to go.
She may have diarrhea when she is going through the treatment, but you have no choice, the heartworm treatment is crucial and needs to be done ASAP, it is a priority.
I assume the shelter is paying for it.
You said this is your first dog, this may not be a good match considering the dog’s medical issues and ongoing care she will need.
If you are not up for it, if your gut tells you it won’t work, talk to the shelter NOW.
There are experienced pet owners that will be better able to take care of her.
If you return her to the shelter, they will most likely place her with a foster while she recovers.
Take a break, and next time get a dog that is doing well, and is younger.
If you decide to keep her, work closely with your vet, ask if she’s dehydrated? Sometimes they need subq fluids once or twice to get them over the hump.
This is not veterinary advice; consult your veterinarian.
