"This week was exhausting"

• Weary worker's sigh
• End-of-the-work-week cry, briefly
• Workweek-ending abbr
• "Finally, the weekend!"
• "I've waited all week for this!"
• Pre-weekend shout
• Working for the weekend letters
• Exclamation around a water cooler
• Employee's cry on the fifth day

Douglas Harper's Etymology Dictionary Word definitions in Douglas Harper's Etymology Dictionary
also T.G.I.F. , by 1946, slang abbreviation of "Thank God (or "goodness"), it's Friday" (end of the work week).