It sounds like you may have a timer problem. It is supposed to back-wash the zeolites sometime in the wee morning hours, flush the hardeners down the drain and replace them with sodium from the brine tank. Something turned on and forgot to turn off but, there are so many different brands and kinds it would be hard to say where the problem is. If you have a book that came with it you could look at the troubleshooting guide.
There should be valves that will allow you to by-pass the softener altogether until you can find the problem. Also check for the drain for the softener, maybe it is obstructed.
Just a general clue finder would be to take the cover off the timer/valve and see if something in there is stuck.