We've had Olivia for three weeks, we brought her home on December 14th...she is JUST NOW not hissing and/or freaking out when she see's the other cats. I thinks girl cats just need a whole lot more time time get used to other kitties and people...even their environment. Her bahavior sounds like she is fearful, but that'll go away with time.

As far as eating a lot, the vet told me the same thing Barbara said above...that, and kittens tend to overeat anyway.

I would take her in for her spay...the vet will be able to tell you if she's pregnant.

Let us know how it goes.