Don't worry about the investor's money - it's called venture capital for a reason.
You've probably learned a tremendous amount from the experience.
Think about what the next step for you is after this company. Sounds like you're a developer and can easily get a well-paying job. Sounds like there is still some money left and you can take some time and decompress from the experience.
This isn't doom. It's the first step of what you're doing next.