Your feeling is mutual.
If it wasn’t for taking care of my dog I would feel useless.
I think you have to have a purpose in like to feel happy.
As we age we are not able to do the things we use to do and it will make you depressed, so you have to find things you can do and do that.
Remember the song by Cat Steven’s “Cat and the Silver spoon”
Listen to that and you will understand why we are in this situation of feeling alone.