Is My Guinea Pig Pregnant?

Yes she is and when they start sucking back water and devouring food that is a sign she is, normally. U should give her some hay to nest In and soon she will be pulling out her chest fur to make a soft padding for her nest. But I'm sad to say the babies are going to be inbred and the mom and babies will possibly but probably die unless immediately taken to the vet. And inbred also mean the babies wil be born deformed.