Hello,
All dogs pant when they are hot, they do not have as many sweat glands as humans and this is a natural way to cool down. Pugs have a recessed face and thus will pant more then the average breed.
The problem is this has been ongoing for 3 days and that is not normal. Her lack of appetite and the vomiting is also a concern since this has been going on.
Dogs also tend to pant when they are anxious or under stress. If there are changes in your dog's environment (e.g. a new family member, or you have just moved), your dog may pant more heavily than normal for the first few days. Try to calm your dog and spend more quality time with her. Use some natural calming remedies if necessary.
If this is not the case then we look at medical reasons for this.
Fear or excitement; Fever; Anemia; Heartworm; Congestive heart failure; Hypothyroidism; Poisoning.
Can all cause heavy panting. But so can heat stroke. Heat stroke is perhaps one common cause of heavy dog panting that can lead to devastating damage to the dog's physical health. If a dog is left in a parked car on a hot summer day, or has been out playing or running for a long time in the heat, he can easily get heat stroke. If he has been out in the heat a lot, of has over exercised in the heat then heat stroke is a real possibility.
Either way this has gone of to long and he needs immediate medical care. Please do not put off getting him seen today. Call your vet and try to get him a appointment today. If your vet is unable to see him today then you will need to take him to your nearest emergency clinic.
Walter
Breeder
Breeder and pet health consultant. Have spent a number of years with dog rescue, training and health