My 2 year old female spayed indoor housecat is acting very odd. The fur on her back is spasming and she spins in circles licking and biting various areas of her body. She will then run wildly a few feet, stop and begin to lick profusely once again. She seems very agitated and is even hissing at me and the other housecat whom she grew up with. I have checked for fleas but see now - she has been treated with advantage flea medication but is due for another 30 day dose. Now she seems to want to hide in small, dark places that she normally would not go to. What could be wrong with her??