Do URIs just "go away?"

Last night one of my cats really scared me. She wasn't there for dinner, and wouldn't come when we called. We found her "hiding" in our bedroom in a corner and she wouldn't come out. We took her downstairs & she wouldn't eat - just ran back upstairs.

Long story short, my daughter went to check on her, and she followed my daughter downstairs and sat by me and I finger-fed her some baby food. There was some yellow gunk in the corners of her eyes (just a little) and her third eyelid was pretty bloodshot. I was thinking maybe she had a sore throat or something & that's why she didn't want to eat.

Well, this morning, she got up and followed me around like usual and ate TWICE before I left for work! So if she had a kitty cold - would it just go away like that?

If it was virus based, just like the common cold, it can just go away. Many vets prescribe anti-biotics to ward off secondary bacterial infections, not to cure the URI.