Do you know anything about depression in people? 
Depression is rough for sure -- I have personal experience with it. It can actually be a symptom of some diseases or a side effect of some drugs.
I experienced it after taking a very strong antibiotic. I didn't know that could happen! 
How did you feel? There's such a wide range of effects -- sadness, anxiety, emptiness, hopelessness...
I realized I was depressed after sleeping when I should have been working. It lasted more than a week. 
Sounds like Major Depressive Disorder. How was your self esteem? It can significantly reduce it.
I didn't have that issue since it was a side effect of a medication. I have a great doctor who recognized what was going on. 
That's good. Was it a medical doctor or like a psychologist? I saw a psychologist for mine and she used cognitive behavioral therapy with me. Great mental health improvement.
It was a neurologist actually who suspected. I had severe issues happen from the med which was shocking. 
Wow that's fascinating. We've come a long way in our understanding of mental health since psychology began with the opening of the first clinic in 1896!!!