Healthy dog keeps throwing up and falling over????

I've had this with a cat as well. Eventually I deleted the cat because it didn't stop, sadly. It was indeed after my cat got sick and I took him to the vet clinic (owned by my sim) to treat him myself. She didn't fall asleep, she just kept falling down. She also threw up everywhere, by the way, it was very annoying, and made me feel a little bad for her.