I am so very sorry you are suffering. Loneliness can be so brutal. There really isn't a vocabulary to adequately describe how awful it can feel.
One of the things that helps people in general is to feel that they are not the only ones going through a certain struggle. So your post today will help members here going through the same or similar situations as yours. It will also help the many people who read these post anonymously. It helps me too.
That is a tremendous gift to give to others. No one who would give such a gift could be a person who "doesn't matter." You matter plenty!
I have been helped by reading posts like yours. Once when I was in one of my darkest depressions, reading posts here kept me going and saved my life.
Saving someone's life is probably the greatest thing a human being can do in life, so I think of you as a very noble and heroic person.
Wish I knew how to help with your loneliness. I lean on people here for friendship and understanding and it helps me.
I am so sorry for your losses and your health problems. Those must be incredibly heavy burdens to bear, crushingly heavy.
Hope you will keep posting here so you will not be all alone with your pain.
Sorry for not knowing how to be helpful to you. My heart goes out to you!