Whenever I get negative thoughts/feelings, I allow myself a set period of time to 'wallow' in whatever it is. Then I have to tell myself that time's up, and focus on the good. Some days it's more of a struggle than others, but having a journal helps. Mine is a list of accomplishments - I'm trying to list everything I've accomplished in my life, and that seems never-ending. I also have a gratitude journal where I catalog things to be thankful for. I've become much better at the gratitude thing and can even be thankful for things like having a pile of dirty laundry or having a problem with the car.

Fixing or maintaining self-esteem takes practice, practice, practice. I have to have my positives lined up before I get in a funk, because when I'm down it's really difficult to find something positive to think about.

Hope this helps.