Spiraling depression. A condition in which a person feels that each day they live is worse than the preceding day. Most generally, this phrase applies to individuals whose personal lives are merely stagnant, rather than actually becoming worse by the day, as might be the case for a starving refugee or a cancer patient.
"Peter Gibbons: So I was sitting in my cubicle today, and I realized, ever since I started working, every single day of my life has been worse than the day before it. So that means that every single day that you see me, that's on the worst day of my life.
Dr. Swanson: What about today? Is today the worst day of your life?
Peter Gibbons: Yeah.
Dr. Swanson: Wow, that's messed up. "
Office Space, 1999
People who exhibit symptoms of worst day ever syndrome are urged to immediately seek professional help -- or to acquire a social life, whichever seems more feasible.