alot of this sounds like extreme anxiety. anxiety can manifest in MANY ways. also, it sounds like you experience some depersonalization with the extreme anxiety...which can bring upon panic.

i'm by no means a dr. i'm just speaking from personal experience and what i've been told.

have you thought about seeing a therapist? a dr can only go so far with this and treat with meds. a therapist can help you to pinpoint the reasons that trigger these and to develop coping mechanisms that can make your life much more at ease.

dealing with constant anxiety is so hard. since you've had complete physical checks, i would bet good money that this is what you're experiencing and seeing a good therapist for 6 mos or so could help your life tremendously.

gl and let us know what you decide?