I tried a lot of different apps to keep track of how I feel but this one works best for me. I use it for my morning and evening journal, keeping track of how I feel (which they made very easy to do) and keeping track in which categories I need to invest more time (family, personal development, finances, etc).
They do need to work out a few bugs and ux design elements, but overall it’s, for me, the best app to keep track of your mental health both through the iOS iPhone/iPad apps or web (I prefer web because of a few bugs/ux issues).