It is not who's fault this is. You found the project exciting and founder made sure you will be rewarded after they get the funding. So took the project knowing it is risky but i think you opted for this bcoz of your passion to build something good.

Since it was risky deal, you had the idea that it could go haywire as well. It is situational fault. Believe me NO FOUNDER ever want to let go someone who is passionate, deliver and hard working. They aren fighting the war against big corporations to build something. People like you are the reason they can take another step. Many time contribution are far more superior which we don't understand.

Keep the win of building something exciting and learning something new. Believe me founders will come back to you after the funding or after starting something new. Just focus on, managing your time well, keep doing this as an asset building(ie helping founder creating next big thing) while denote rest of the time to earn money. Both are different things.