。
The days when I held back my tears.
Literal
Tears [object-を] held-back [past-た] days.
A nominal phrase rather than a full sentence — reads like a song title or poetic fragment. こらえる ('to hold back, endure, suppress') — often paired with 涙. The past form 涙をこらえた modifies 日々 ('days, days on end') as a relative clause. Poetic/reflective register.