2 1/2 year old mix dog is starting to be very protective...?

my 4 1/2 yr old dog had a litter of puppies about 2 1/2 years ago. of course i kept one of the puppies who i named jewel. jewel is now 2 1/2 years old. she had a toy ball that she was very attached too. and when i say attached i mean OVERLY attached. she would pick up the ball and just walk around with it in her mouth and cry! sleep with it even try and clean it! i think she was treating it more a puppy. the other day we were all together in the living room, jewel was laying with her ball in the corner as my youngest brother came over to her and she snapped at him in his face ( thank god he moved)! my boyfriends promptly took the ball away and threw it in the trash! so the next day we got another toy for the two of our dogs (diamond & jewel). jewel took the new toy ( stuffed chipmunk) and immediately started to act as if it were her puppy AGAIN! jewel is not spayed and another thing is if u pick up a toy jewel will not take it from your hand she will only lick it and whine... i'm worried that this behavior is unhealthy for her and for the people around her!!! PLEASE if any one has a dog that has done this let me know what to do !! thank you !!!!!