I read this once and always use it when I'm fretting about something that is stressing me out. It always puts things in perspective.....
If you only had one day to live, what would you want to do, what would your thoughts be, what would be important? Your job is probably not at the top of the list since it's probably not so important in your life.
For bad days, know that they are not forever. Take short breaks if you tire easily, a walk to the restroom, get a cup of coffee or tea, stretch. For ignoring those frustrating co-workers or duties you just hate, bring something to work that makes you feel happy and focus on it when you're stressed.
Know that your already accomplished the hardest job in the world....raising 5 children. If you did that, you can do anything.