Your pup needs to see a vet today. There are many things that can cause that from an injury to their throat to poisoning or liver or kidney damage or internal injury or lots of other things. Your vet will know more after being able to examine your pup and talk to you about everything. They will most likely ask you about anything your pup may have gotten into, been exposed to or that you have may have given your pup (like our meds) recently so start trying to think back over at least the last week and not just a day or two if your not sure of anything that could have caused a poisoning and that could be it. Hope your baby is feeling better soon.