I am desperately looking for a German Pre-teen/ kids book…

I am looking for a German pre-teen book about a teenage girl who develops unusual powers and is then driven to her grandma's house to investigate the powers. On the way to grandma's house the girl was sick (high fever) and slept in the back seat of the car. The mother was a single parent. There are several parts, at least i think so. It was on Spotify as an audiobook. The girl could turn into a cat, or atleastthere was a cat involved and I dont know but she could talk to animals. The villain was an old witch with magic. The grandma and mom didn't have much contact (but it could be the aunt and not the grandma, i am pretty unsure). I am going insane cause I don't know if this even exists or if I am just remembering parts of different books. If anyone knows what I mean pls tell me I am going nuts