(((((((Jinnyann))))))))))))))
I have to ask this-did you have/take anything with caffiene in it? Coffee, Tea, Chocolate, Midol, Excederin, etc...?
If so, then that may be contributing to it-also, if you take sleeping pills over a long period of time and then cut back or stop, that can start to make you feel jittery and ill at ease, too.
If those two aren't the factors than there's something that's hiding inside your head that you need to bring out into the light. Do you fear being ill? Are world events concerning you? Is any family member sick?
Can you try to pinpoint where these feelings of panic are coming from?
It's only a start but it's something you could work with.
Hope this helps a little bit.