I get that it feels a bit unmoored when there are no people or things relying on you.
That said, they are not what gives life meaning. Your life doesn’t need to have a point- you don’t have to be something, achieve something, or be a resource to other people. All those are good if that’s what you want, but they aren’t the point of life.
I felt massively adrift at various stages of my life, and got myself pot plants, fish and eventually a cat. They noticed when I was home, and appreciated me looking after them. I liked that.
I am also religious, so get comfort, challenge and purpose there.
But you don’t have to have purpose/point- you can just be. That’s ok. Personally I like ‘being’ better with a bar of chocolate and a good book! Do small things that are enjoyable- scented candles, baths, wine, crisps, puzzles, books… whatever you like. That’s enough.
On the other hand if you want to achieve something, volunteer or start some hobbies. But it’s for you- what you would enjoy.
You are enough, even if you don’t.