Possibly the refrigerant lines have come loose from where they were attached. You might go to the air handler and put your hands on each line and have someone then call for AC. You should feel the vibration as the refrigerant starts flowing. In the beginning it's a combination of liquid and air but after a few minutes it should be only liquid. The initial vibration should stop in a minute or 2. If not and you can hear the flow you may be low on refrigerant. I am a believer in having a sight glass at the evaporator coil so you can always tell what's flowing to the coil.