I can sympathize. I have gotten panic attacks off and on for almost all of my life; including my childhood. I know the feelings of out-of-control, and of doing or saying things that are not in line with your normal self.
I have found that "grounding" myself helps. Not grounding as in punishment! Grounding, as in, being aware of my feet and their touching the ground. And being aware of what is around me (since my attacks often occur while driving) I will squeeze the steering wheel.. I will even sometimes bite my lip (not hard) and I do realize that this oculd feasably border on self-harm (that is another topic really) but it does help me to rein myself in and take back control.
Hugs.