It turns out that Sonja has chronic kidney disease. The vet will be calling me again today to talk in detail about what course of action needs to be taken to prolong and keep Sonja as happy and as healthy as possible. Also, he is concerned that she may in fact have heartworm as well. But since that is what they were not looking for initially, he says there is a possibility it could be a false positive. We will be doing a heartworm test when Sonja goes back to get her stitches removed. Poor girl, I just want her to have a happy and healthy life.