When it involves anger (not grief or sadness) I have my surefire-for-me method. When I am stressed and angry, and cannot sleep because I am too worked up, I put my glasses back on, get a pencil or pen and a piece of paper, and make a list.

I make a list of things I hate. It always, always, always starts with "canned peas" even though I have not even encountered them for years. That's an all-abiding hate from childhood. It moves on from there, and includes anything that really annoys me, and eventually I even usually get down to what I am actually angry about, and by the end, I can relax and get to sleep.