دارت means Revolved. دارت بية الدنيا his situation changed to worse. You can say it for someone who was on good state but because the life become harsh he/she lost his/her wealth.

تقلبت

دارت بية الدنيا is not classical arabic , it seems the Tunisian dialect and it has the meaning of something bad happened to (myself) and دارت means turn around in general

Turned around