Grief-What is it?
Pain? Loss? Abandonment? Rejection? Feeling lost and alone?
These and more perhaps. I think for everyone it differs, depending on what the situation is.
There is a model on grief The Five Stages of Grief. It describes the stages we go through, and what we feel, in no order as we grieve. There is no set time limit on it. Grief takes how long it is needed to deal with the process of the situation.
Image credits: Featured, by A Poet in Time