Leave. Your hard work is being wasted there. I was in almost an identical situation. When I left the company folded, but funding was getting short anyway (the first time a check bounced I used that as my excuse). The boss won't be happy, but you can only go up from where you're at.
Happy side note: 10 years later I'm running my own startup (only founder) and it's great. However, working in big companies between the two was definitely helpful.
Happy side note: 10 years later I'm running my own startup (only founder) and it's great. However, working in big companies between the two was definitely helpful.