In becoming depressed, you have nothing to blame yourself for and nothing to feel guilty about. A predisposition toward depression can be hereditary. So, for heaven's sake, don't blame yourself. Don't even blame yourself for blaming yourself. It's not your fault.
Guilt is the mafia of the mind.
It's not your parents' fault. It's not your spouse or lover's fault. It's not your children's fault. It's not your boss's fault. It's not society's fault.