Babysitting

So I baby sit a 1 year old (about to turn 2 in a couple of weeks) and recently she started going with her dad from Wednesday to Saturday because yk babymama and baby daddy drama. But she came back on Monday to me and her behavior has changed a lot. She never use to cry like how she does now and it’s very frustrating because it’s like she’s traumatized by going to her dad now. Any help on why her behavior changed??? I guess due to the change of environment. In my opinion I feel like she’s too young to have such a drastic change of environment but hey 🤷🏾‍♀️