okami - you aren't alone on this one! i feel the same way. it is constan! i fully understand what you are going through, and where you are at right now!
these are all just negative thoughts feeding each other - which has led you to the point you're at now.
just remember though - these are the negative thoughts - NOT YOU!
you aren't always in this heightened state of emotion. you have just led yourself down this path by feeding the negative thoughts - i do it all the time! it's a nightmare, i know!
you will get through this though. you just need to ride it out.
every negative thought you get, just leave it there - don't acknowledge it. like, if you think of something in your past that bothered you, don't even think "it's in the past - there is no reason for it to bother me right now" ...even that is feeding your anxiety.
jessed has told me quite a few tmes to just let the thoughts be there. watch them, don't respond to them in any way! just leave them be.
distract yourself in whatever way you can! play an online game, do some housework, put your music on and just try and forget about everything. even for 5 minutes just to let yourself cool down and have some head space!