It took 4 months and shared trip to the groomer before my 2 year old did anything more than tolerate a new addition to our furry family. If you are the second new home for her in just 2 months, she me be stressed a little and this could cause her appetite loss and lethargic behavior. Then again, she may just have a laid back attitude and laying around is what she does.
Do you know much about her previous life? Could there be some trust issues or abuse?
I worry about her growling at her previous owners...
I would take her to the vet to make sure she has not health issues that could be causing her pain or discomfort.
Keep us posted.