Did Saint Patrick get taken to Ireland where he was sold as a slave?

Yes. At the age of 16 he was taken by Irish pirates from Britain to Ireland and sold as a slave to a Druid Chieftain and forced to herd sheep for six years. In a dream one night he received a message that he should immediately leave and walk to the sea as a ship was waiting that would take him home. He abandoned his sheep and left, finding things exactly as they had been predicted. Some time after arriving home he received a new calling to got to Europe to become a priest. Once he completed his studies Pope Celestine I made him a bishop and sent his as a missionary back to Britain and Ireland.