One thing that helps me when I'm depressed is to avoid things that are sad or distressing. I tend to surround myself with humor. Even if I'm not laughing, at least I'm not watching other people crying. It does seem to help me. I kind of figured this out by accident because I have a very long, deep depression when I was a teen, and I just would watch stand up comedy blank faced.

Also, another thing you can try is exercise. It may not be something you want to do, but it can get the happy chemicals moving. You kind of have to force yourself. I'm not very good at it but I know it helps other people.