I'm thinking you have a typo there with a 17,000 square foot home, maybe you meant 1,700?. CA is not known for cheap rents but I've seen many posts where relocating to another state makes more sense. If your on ssi and don't need the job market, can you imagine how refreshing a small town in another state could benefit you?
Maybe it's time to look at some of the surrounding states for more affordable accommodations.
I hope your situation improves soon and hopefully life starts looking a little more positive for you