My pittbull?what can be wrong with her?not eating?

i was given a 11 month old pittbull a week ago,she is a alligator watchdog breed,well she barley eats,all she does is lay around,i take her out all day long to pee or poo,i am still haveing trouble with here using it in the house,in the morning theres a mess to clean of some kind from her,she was raised with a male pitt and her owner since she was 4 months old until i got her,today her food and water has sat,she just layes there,i have wormed her,she has toys,food,clean home,lots of love,i am worried,what else could i do for her,she is so sweet of a dog,she is real skittish i have noticed,scared,i try to make her feel comfortable as i can,but she just lopes around,