I am not going to diagnose your symptoms, but it sounds like you are
experiencing a panic attack.
Panic attacks are typically characterised by heightened anxiety causing
you to overbreathe. Basically your bodies natural flight or fight
response to anxiety. If you then misinterpret these symptoms (its
called misattribution) it will further increases your anxiety, and often
result in hyperventilation, which will cause the types of symptoms you
are referring to.
Its a very common experience for those of us who have panic disorder,
and if you are getting these regularly I suspect you may have
developed panic disorder rather than just GAD.
In short reading some of the info on this site about panic attacks, the
cause and ways of dealing with them. A therapist can help you with
psychotheraphy and cognitive behavioural therapy, and a GP can
prescribe a variety of medications to assist you with this type of
problem.
Its always best to get it diagnosed by a professional - self diagnosis is
really dangerous.
There are however some wonderful programs you can do yourself,
typically called Self Mastery Therapy/Training which help immensely in
recovery from panic disorder.
