Sounds like you have had a nasty panic attack.
1) Its quite likely what is happening is you are feeling anxious,
overbreathing (a natural reaction to anxiety), feeling more anxious,
hyperventilating, experiencing hyperventilation symptoms (pins and
needles, dizzyness, cant breath etc) and then panicking about it.
A psychologist can help you with dealing with these symptoms, also a
dr can prescribe you medication to help to feel better (preventative) or
to relax (reactive) which will help you cope with the symptoms.
If you have had medical tests and they have ok'ed you, it is most likely
this is what is happening. When we get anxious we overbreathe, and
then eventually hyperventilate. It feels terrible, but understanding
what it is that is happening to you usually helps you to do something
about it.
