Hello. If she had a normal bloodwork, it is very unlikely that she has a serious disease like cancer. The fact that she is playing normally is also a positive factor, and one that does not suggest depression
. Is everything ok at home? The relationship between mom and dad is ok or has changed lately? Do you have a smaller child? All those factors could be contributing to that. Try interacting more with her without pressure. Go out, do new things that she might like, and talk to her. If nothing works and you think that the situation may be worsening, consult with a different doctor.