Depression’s a bytch. You are questioning life itself because you are in such a disparaging situation. I believe some people suffer from a depression that is not due to a situation and must be biological, but I know of your situation so I mention that as a cause for your questioning the point of living. Someone who is not severely depressed has enjoyment in some things at the very least and feels good to be feeling some pleasure.
We could get into a philosophical discussion about what we think is life’s purpose, but no one knows. Who knows if living even has a purpose? But we are here, so I say just go with it. Do you best to make it a good life.