Yearning

An emotional state of intense desire or longing feeling for a person, place, or thing that is treasured in the past. Yearning may also be experienced as part of the grieving process.

Reference:
Haley, E. (2017, March 14). Yearning in grief and loss. https://whatsyourgrief.com/yearning-grief-loss/

O'Connor, M. F., & Sussman, T. J. (2014). Developing the yearning in situations of loss scale: Convergent and discriminant validity for bereavement, romantic breakup, and homesickness. Death Studies, 38(6-10), 450–458. https://doi.org/10.1080/07481187.2013.782928