Warning: amateur diagnosis follows… I’d say you’re in mild shock, both emotionally and physically. The physical side of that will cause your body to go into ‘survival’ mode, keeping the core warm and alive. *All* extremities are considered expendable (by your grieving psyche) and won’t be at the head of the list for nourishment. (If you were in traumatic shock, your blood pressure would plummet.) You may actually feel chilled, even in a warm room. I’m afraid I’ve been there many times, and my sympathy goes out to you. You need to slowly regain balance in your life. Force yourself to participate in other activities. Get out of the house. (I often sought out a book store and treated my self to a book or magazine and a coffee.) Connect with supportive friends, even if it’s just sitting there silently sipping a cup of tea or watching TV together. In other words, you need to stop the slow decline and realise that life goes on. It will take time. Perhaps PE is a good option to divert your mind and give you an achievable goal which will make you feel good about yourself. (After my divorce, I threw myself into the Y and outdoor activities big time.)
Just my 2 cents worth. Good luck :-)
One final thing: the universe is an odd place. You will find someone else, and incredibly, she will be even better for you. I’ve been continually amazed by how often this has happened in my life.