My diabetic dog won't eat and drinks a lot. Why is this happening?

I am very sorry to hear that you are experiencing these issues with Matilda. These clinical signs, inappetance and increased water consumption are unfortunately very common for diabetic dogs. Because Matilda's body cannot handle the Sivan she eats in her food in a normal way, an excess amount is passed through her urine. The sugar drags water with it, meaning that Matilda will urinate more of her water intake and reserves then a normal dog will. Keeping her insulin medication and feed intake carefull monitored will help slow this diuretic effect and keep her more hydrated. The same issues with handling sugar inside her body can affect her appetite.

If you are noticing that these problems are becoming worse, I suggest a recheck with your vet to make sure that the medications are at an appropriate dosage, and that there aren't any complicating factors present, such as a yeinary tract infection, which are common in diabetic dogs.

I hope this answer was helpful, and more
Importantly that Matilda feels better soon. Warmest regards to you both.