One of my cats, Lulu, 8 months old female, started acting slightly different today. Usually she is very active and extremely playful but today she seems sleepy and kind of tired. And she also is being overly affectionate, won't leave me alone today, starts grooming me out of nowhere. But the one thing that scares me a little is that her third eyelid is showing, mostly when she is falling asleep or grooming herself (which I know is normal). It does go away if she gets alert but very slowly and a little bit of it is still showing, I have never noticed that about her before. I am going to take her to a vet but probably not very soon because we have just payed a giant bill after taking both of my cats for their first vet visit. I just want to know if I should be concerned about it and take her to an animal hospital immediately?