We all have bad days - they are just part of life. A bad day doesn't mean a bad life. In fact, several bad days in a row doesn't mean you have a bad life.
I have always followed this simple rule: Whenever it feels like everything is going wrong, just wait 3 days to see if it improves. It always does... especially when you are looking for signs of improvement! I find myself focusing on all the ways my life is looking up and before I know it life is good again!