Have Cat Questions? Ask a Cat Vet Online.
I am sorry to hear you are worried about your cat. My name is Rebecca. I am a veterinarian and will do my best to help.
When she was at the vet, and her weight was considered fine, had she lost or gained any weight at all?
Is she drinking any more water than usual; eating normally?
Hiding can indicate a cat is not feeling well. It can be pain, internal illness, or stress from something that scared her like something she saw outside (a dog coming near a window, a cat fight she witnessed, etc.). It is good she just was checked out and seems to be fine, but if this continues I might consider doing some basic blood tests to learn things I can't learn about on a physical exam: kidney function, white blood cell count, liver values, blood glucose, etc.
Let me know what other questions you have.