Marriage is a permanent covenant between a man and woman. It cannot ever be ended in the eyes of the Church (“What God has joined, let no man separate”). Therefore, a civil divorce is a legal proceeding, basically the end of a contract. However, an anullment is different. An anullment is basically a decision by the Church (through a marriage tribunal) that for one reason or another your union was never a marriage. The only way the Church will marry you “again” is if you were never married in the first place. I would speak to your parish priest about how to begin the anullment process.