Is my divorce valid without court involvement or hearing?

I got married this year in February to my boyfriend through a registered marriage. I only signed the marriage documents and did not perform any other ceremonies. After 4 months, his father started pressuring us for a divorce, so we went to the registered office in my city and signed a divorce on stamp paper. There was no court involvement or hearing. Is the divorce valid? I urgently need your help, as I still love him and don’t want to leave him.