Most of my problems stem from my low self confidence. Here is an article that has some good things to say about this issue. Most of them are common sense but even so, they are things that I tend to forget about when they are most important.
Other things that help me a lot and almost immediately (like within a day) are getting enough sleep, exercising, eating well, hot showers, tea, positive people, laughter, being alone for a while and just chilling. I’m an introvert and I guess I just recuperate by having a little time to be alone.