Getting lost in some other world - a book or a movie. If my thoughts are bringing me down, then I need not to be alone with them, and that's when getting outside with people or animals is the best.
Another thing that is awesome for me is photography - not that I do it much anymore. I'm no photographer with fancy equipment or anything like that, but just an ordinary camera with a lense I can adjust. What's great about that is it focuses me out of myself. I totally forget me while I'm focussing on the best shot. Once I break the connection with "me" - even briefly - I'm okay. Once when I was focussing on some wildflowers, a tiny cabbage butterfly fluttered out from among some leaves, for a split second I didn't know if I was me or the butterfly - sounds like a Zen haiku, I know, but it really happened. It was wild.
I need to go back to that again. I think that's what art's all about.
If I need to get my nerve back, then I listen to "Blaze of Glory" or "Bad Company" by "Bad Company." You're probably a lot younger than me, though, so the songs won't do the same thing.
Salmon leap from the womb of the white sea you look on; they are calves, they are lambs of good color, in peace without slaughter.