So, I came home from work on Monday and found her laying motionless on the bed. She wouldn't purr and was breathing funny. I was able to get her up but she was still acting very peculiar so I ended up taking her in to the emergency vet. They checked her out and did some blood tests but the only thing that came up was elevated glucose. I have a follow up appointment at our own vet (much cheaper than emergency care) to do some more blood work. They think she may have diabetes. They also said it is easy to control in cats with just a change in diet (to canned food only).
The day after she was acting a bit better and by Wednesday you would never have known she had been acting like she was going to die - other than the patches of fur they shaved off to get the blood. I'm just happy that it wasn't anything too serious.