I agree with Bob and Lapis. As Lapis stated, and I started my post out, it may be a food (additives too) allergy. But, anxiety/panic attacks are not always because a person is stressed about the situation. For example another quote from that site is, "A panic attack seems to come out of nowhere—at times and in places where there is nothing to fear."
LOL- and if I am with my family too long... I am surprised I haven't had one yet:)