The following is a summary/excerpt of Sorge (Care) in Michael Innes Heideggers Dictionary.
Heidegger uses three cognate words in the description of Care:
Sorge - properly the anxiety, worry arising out of apprehensions for the future; and refers as much to the inner state as well asexternal cause.
Besorgen - to get or provide something for oneself or someone
Fursorge - actively caring for someone who needs help; thus welfare (as in organised by charitible bodies or the state); or solicitude
The concepts are distinct in that Sorge pertains to Dasein itself; Besorgen to activities in the world; and Fursorge to being with others.
Sorge is the dominant mode of the triad, but inseperable from the other two; as a concept it distinguishes Heideggers project as phenomenological rather than objective and theoretical; our primary attitude towards the world is not cognitive as in Descartes & Husserls 'concern for known knowledge'; Heidgger indicates a temporal structure to this triad:
Sorge is concern for itself; and thus reflective; and thus concerned with its past.
Besorgen by being concerned with others is concerned with the present.
Fursorge by being directed to others (and not things); it thinks of the future and 'leaps ahead of the other' to give Sorge back to him.
Sorge thus unifies three features (or dimensions) of time: existentiality or being-ahead-of-itself, facticity or being-already-in-a-world and falling or being-alongside with others. Thus future, past and present; thus 'temporality reveals itself to be the sense of authentic care'.
Thus time in Heidgger relates not to the linear Newtonian dimension of ceaselessly regular and objective flow - physical time; nor to the cosmological cyclical time of the Vedas but of being here now, with a past behind us, a present at-hand, and a future ahead of us; and this is understood for an I, a You, a They and We and not for things.