Hard breathing? Do you mean you're worked up, so are "panting" from emotion, or you are finding it difficult to breathe? If you are having trouble breathing, please go to an emergency room right away.
If you don't think it's an emergency:
Try consuming something that has some carbohydrate in it. You might be having a low blood sugar problem. What kind of carbohydrates can you tolerate? I normally recommend juice, but we don't want you to dump. Milk might work, applesauce, etc.... then follow it up with a protein food.
Give your surgeon or doctor a call today to see if they can see you. You might be short on some nutrients, or it could be coming from a physical problem (if you don't have a pain or fever, it's probably NOT a problem with the surgery).
Many people have crazy mood swings post op, but I think this probably has a physical cause.