A mood tracker is definitely on our list of features to add. We'll let you know when it's available. Thanks for the suggestion!
The mood tracker is now available. Go to My MedHelp and click on the Trackers Tab. If you don't have any trackers, you'll see a list of all available Trackers. If you already have trackers, click on the Trackers icon on the right of the toolbar and you'll see a list of trackers you can add.
Thanks for the suggestion and please let us know if you have any enhancement requests.