Ah yes, I hate when other people (or even myself) points out the obvious, that it will end or is not real, etc. and it doesn't help at the moment. I use to get almost suicidal a few days before my period when I was in my mid-20's and it didn't matter that it was related ot my period and I knew it would go away in a day or two.

You got any things you really "love" a "happy shirt" for example that you could go put on or a ritual that is calming you can go to and do? Don't bother arguing with yourself if it doesn't work! If you feel horrible, do it "right" and feel like you feel!

Another thing to try; maybe you can distract yourself by "exaggerating" how you feel? If you're alone and feeling paranoid, start looking under the furniture :-) anything that seems "ridiculous" and might make you laugh. If you feel like you're going to die, lie down on the floor or something, exaggerate/act out the feeling? "Go with it".