Distracting yourself (as suggested above) is a really good idea even tho it's only a temporary measure because if you can focus on something outside yourself, anything really, it will help you pull that energy out of yourself, you know, the energy that's pulling you down the vortex.

An example that happened to me once: I was on vacation descending deeper and deeper into my depressive, self-destructive thoughts, contemplating the worst, when I looked up and all of a sudden there was a squirrel right in front of me - looking at me, curious, flicking its tail. For some reason that little animal pulled my energy right out of myself, to something on the outside, and I was OK for a number of hours after that.

Anyway, sending you much love and support.