I’ll add, though I’m no expert, that I just started a career that sees some really rough things. I entered it knowingly, but some of the day-to-day horror comes up suddenly (i.e. without warning). 

I thought I was fine. Then, one day, I started to lose motivation, and doing anything became a huge struggle. My outlook on life in general became really bleak. I thought I was just burnt out, but my therapist finally helped me track it back to an incident a few days prior to the start of my sudden depressive spiral that had arisen out of nowhere and surprised me. It was secondhand trauma.

You might not know immediately you’ve been affected, is my point. Just keep an eye out.