Well it depends.
I have was diagnosed with depression and anxiety, recently my doctor advised he believes i have ptsd from a very traumatic childhood
I have made changes. But honestly I have felt like this for as far back as I can remember and I am 37. I have been to the doctor before (when it's for really bad), offered counselling and tablets. I never followed it up, because I didnt want to have that label of being mentally ill.
It has got to the point to where I cant function. So yes, I have made changes but not all of them.
I am chronically unhappy. I have changed jobs, moved areas, exercised worked part time/full time, cut out caffeine etc.
I think you are underestimating what unhappy can mean. I didnt want to admit I am ill. But I also wanted someone to pull me out of the hole I am in.
It was confusing and panicked me. I wanted someone to save me, when I wanted to pretend I was ok and no one knew I needed help.
Ita sad to think that people must think I am just unhappy, not ill because I couldnt help myself for a long time. I went to bed most nights hoping I didnt wake up but couldnt help myself either.
Its hard to understand myself, so no wonder other people dont understand.