Prayers for little Bella and for you.
Since you do not yet have a diagnosis, please do not worry and let your fears take over.
First thing to do is to get a diagnosis so that you know exactly what you are dealing with.
Do not let ANY diagnosis frighten you without the full evaluation and prognosis coming from a vet. Just in case it does end up being hydrocephalus I want to share this with you. YHR had a hydrocephalus pup last year. He was surrenderd to us by his owner because she could not afford an mri for him. He ended up just fine and has a wonderful home. Below is a link to videos of Samson....I am also going to find his bio and post it here. You do not know yet that Bella has this, but I want you to know that it is not always a horrible outcome:
www.yorkiehavenrescue.com/samson.html