The Current State Of My Being Is Very Perplexing. I

the current state of my being is very perplexing. I am not sad and I enjoy work; what concerns me is that I have lost all interests in doing anything. have given up all my friends, hobbies, running and cooking. My husband is a loyal and wonderful person and I should feel so happy. both our children have grown up and are well and I am still listless. All I want to do as soon as I get home is sleep or watch TV. I used to read constantly and now a book as to be so good for me to sustain my interest. years ago I was on doer and constantly in a project, now, nothing. Dogs both died in that last 13 mths and both children have moved on with their lives. What can I do to get some improvement.