i'm surprised nobody has mentioned that it may be a panic attack.
have a quick read up on it caramel, if you don't already know what one is...it may fit.
OMG THAT IS SO USEFUL I have had those before THANK YOU SO MUCH

:D:D:D
"A panic attack is a response of the sympathetic nervous system (SNS). The most common symptoms may include trembling, dyspnea (shortness of breath), heart palpitations, chest pain (or chest tightness), hot flashes, cold flashes, burning sensations (particularly in the facial or neck area), sweating, nausea, dizziness (or slight vertigo), light-headedness, hyperventilation, paresthesias (tingling sensations), sensations of choking or smothering or derealization, the feeling that nothing is real. These physical symptoms are interpreted with alarm in people prone to panic attacks. This results in increased anxiety, and forms a positive feedback loop.[4]"
Although this is not what I was aiming to describe at all, now I know when I have this combination of things I am not getting sick/dying etc, it will all go away.

THANK YOU I AM FOREVER AND EVER IN YOUR DEBT.
Excalibur I must have had one of those on the AXP night.
also, on the topic of you..
You do know that not everyone knows the underlying condition...
Why would being autistic be relevant to this o_O