I'll tell you all what happened: :( Basically, while I was walking him on my way to the grocery store, he was starting to feel exhausted, and as soon as I brought him home, he started panting and breathing hard. He also often keeps coughing loudly, as if he were about to vomit or cough up something stuck in his throat, only to come back over and over again. I kept asking my family to take him to the vet because something was wrong with him, and today we actually went. The vet examined him and said he has heart murmur and fluid in his lungs, so she needs to examine him within 24-48 hours, putting him in an oxygen cage to help him breathe properly. Furthermore, after the tests, the vet suggested that he should take medication for the rest of his life to keep him healthy. As we were leaving, he was extremely agitated and wanted to scratch his way out of the cage. I was crying! I'm so worried about him! And i hope he gets better soon! :(
[EDIT] My dog is fine now. He returned from the vet.
