Grounds and neutrals are supposed to be connected at the service. Separated everywhere else. If your breaker box is the service then all is well. If the box is a sub panel then call the local authorities and have them look at it.
Simplified explanation Ground is for a return path to the service to help with tripping the breakers Neutral is a grounded conductor for 120v loads.
Have one wire do both jobs has been proven to be unsafe.