If you are stressing out about something, figure out if it is something you can do something about. If it is, don't waste energy on stress, put your energy into doing something about it. If it is not something you can do anything about, don't waste energy on stress, acknowledge it and move on.
Don't ever get convinced that you are irreplaceable.
You don't get extra credit for doing what is expected of you.
Never hang your head in defeat if you truly tried your best.
You have to baby a loser. You can drive a winner. Be a winner and seek other winners.