How old is she?
how long is she hiding like this?
what and when did she eat last?
Cats do not have whims like people. Whenever they start hiding they are either ill or in pain. If her blood work was unremarkable and she has no other symptoms like fever, diarrhea, constipation, infection, etc then here is something going on that is difficult to ascertain - but it exists nevertheless. Sometimes a cat can have an abscessed tooth or root that is in the gum.They can ingest a piece of plastic that in not perceivable in an xray. They can be mildly dehydrated or have a metabolic or organic imbalance that is too slight to read on a test. She may also feel nauseated.
A cats appetite is the best barometor of her health so eating is a very good sign. However, you must pull her out and feel all over her body and look in her mouth for any possible causes.
It may be an abscessed tooth or root in the gum iif you cannot see anything.If she stops eating she will have to be reevaluated ASAP. By then the bloodwork will be in and you will have a better idea what is going on with her.
Please let me know what is happening. I will be happy to help any way possible.
I hope it is something simple since she is eating
Sincerest best wishes,