What sort of clubs, societies and other organisations are there in your area?
Most people live within a reasonable distance of U3A, or clubs/groups catering for crafts, educational or leisure pursuits and so on. Citizens Advice Bureaux will help you find them.
One day a week volunteering is not enough for you.
I often go days without speaking to or seeing anyone.
The difference is, I don't really mind.
To some humans it IS natural to be alone, I'm one of them. In my youth, I dreaned of living in some remote rural area and not meeting another human for months on end - but it didn't work out like that, so I make do by being a hermit in the suburbs 
Although I enjoy company when I can, I have a huge sense of relief when coming home to my empty house, knowing I can close and lock the door on the world.
I've joined clubs and societies over the years but they haven't truly suited me. The subject did, the Trivia club for instance was great and I went for over a decade but I had nothing in common with the other participants.
I've persevered though and still do but I have no feeling of kinship.
I honestly have no conception of what it's like to be lonely.
That may seem like a good thing but I often think I'm too introspective.