not someone's day

not (one's) day

A day that has been particularly stressful, difficult, disappointing, or filled with unfortunate events for one; not a good day. I can't believe I got locked out of the apartment. This is just not my day. I'm sorry, sweetie, I know you studied hard for that test. It just wasn't your day.
See also: not
Farlex Dictionary of Idioms.

not someone's day

used to convey that someone has suffered a day of successive misfortunes. informal
1997 A. Sivanandan When Memory Dies He sighed inwardly, this was not his day.
See also: not
Farlex Partner Idioms Dictionary
See also:
  • not (one's) day
  • not one's day, this is
  • (just) one of those days
  • be music to (one's) ears
  • be music to your ears
  • a black day
  • just another day at the office
  • by the day
  • from day to day
  • make a day of (doing something)