Go in with a box. Fill that box and go out to another room. Start to sort. When done return and do the same. Eventually the space will become friendly again and the rush of memories won't sit on you so heavily as you sit in the room trying to do this.
I find a fresh air place (cold or not open a window or get air moving). Invite a friend to the "new space" for coffee, but the sorting must be yours; perhaps they will visit as you work as well.
This is a tough, but not impossible time. I am with you and know that you will find peace soon.