I had to move back home and spend a lot of time with my family to be reminded that I am much more than a gaijin in Japanese society. I've been out of Japan for three years and I still think about it every day.
You may already be cognizant of this, but I wasn't, I didn't realize how it was affecting me. Do you have family or friends back home that you can talk to about your troubles? This isn't financial or business advice, this is personal advice. I know you're protecting your 建て前 but you should consider that it's just a construct, it doesn't define you, and it's not worth killing yourself over.