What could be wrong with my degu?

My degu is sick. She is really skinny and hunkered down. She won't eat, and she's very disoriented. Whenever she walks, she stumbles and walks in a circle. There's a scab on the top of her left ear, but I'm not sure if that's relevant. I know that degus are prone to diabetes, but I don't know if this could be it or where she could have gotten the sugar. What could be wrong and is there anything I can do?