On returning from a five day trip, I came home to find my 10+ year cat who is FIV+ very lethargic, having trouble jumping up on things, (like the couch) and has obvioiusly lost some weight. My petsitter told me he started walking weird and didn't eat for a couple of days though he ate last night and ate a big breakfast today. Still he is doing nothing but sleeping. I saw him use his box, but I don't know if anything happened in there. He has had urinary problems in the past, but nothing in the last couple of years. It is Sunday, and I don't know if I should pay the extra bucks to go to the emergency vet tonight, or can he wait until tomorrow.?