It is possible you are looking for one of these similar popular tracks:
: A massive hit by Eason Chan for the series Arcane , which often appears in searches for "Lonely" and "Gu". Bai Yu Lonely Night Gu Du De Ye MP3 Download
: A well-known ballad by Guan Zhe (Grady) that features similar themes of late-night longing. It is possible you are looking for one