Though it seems impossible, I find that if I can force myself to get up and move around, it helps loads. Even if its just in the house. Also if I can force myself to eat something, having that energy also helps me move about and I might manage a walk outside.
I tried it after reading here that excersise can help - that doesn't mean doing a full workout in the gym! it means getting out of my feotal position and just moving my body. This forces me to breathe properly and forces a kind of reality into my brain. Not sure if that makes sense to anyone but me but it seems to help.