Oh no, poor Tibbe. Sometimes if Mimi eats really good one day, she won't have much of an appetite the next day, Princess does this too. The boys are hungry all the time. If it's too hot, the girls' appetites will be suppressed too...wish that happened to me.
Princess sometimes refuses to eat unless I take her out walking, then she'll have a great appetite once we get back. I hope it's something as simple as the above for Tibbe & not his liver making him sick.