ADT Alarm System. HELP ME?

Okay, so this morning everything was going fine, but now, when I exit the house by opening the front door it does not say the usual "armed front door" or whatever it usually says. It has says that for as long as we've had ADT , and that has been over four years. I am worried, because I do not feel secure without this. Please tell me how to make the "chime" come back on. I do not know if you should press the "chime" on on the keypad or not. This answer needs to be answered quickly, if at all possible. Please & Thank you.