I so happy you have Mooney home

What a nice person to bring her home. However, the concern is the shape she is in , and the possibility that she was at your neighbors the whole time, and now even pregnant

you are doing what is the the smartest thing, taking her to the vet. See if she is indeed pregnant , than go from there. She is very young herself , and if she is small, carrying puppies is dangerous. However the vet will help you decide what to do.
SO glad Mooney is in safe hands , and back where she belongs