Possible Clues:

• Down mood, with 'the'
• Boredom, with 'the'
• Monday feeling, with 'the'
• The __ (tedious feeling)
• Doldrums, with 'the'
• Vague discomfort, with 'the'
• Vague discomfort, with "the"
• Antonym of ''happies''
• Case of boredom, with "the"
• World-weariness, with 'the'