I have a guinea pig who is around 10 years old, she has been very well taken care of, but I've noticed a significant weightloss with her lately. She still eats/drinks and squeals when she wants a treat as she normally did, but I noticed she still kind of shutting down. She has a black crust in the corner of her eyes that no matter what I do keeps coming back. I think she may be starting to lose her eye sight... I'm very worried about her, I don't have the money to take her to a vet, she's never been ill or hurt. I know she's old, but I just want to know if maybe she's sick and not just, well old.