[pmcgrathm]

While there are objective indicators in terms of product:market fit, your startup has only failed when you let it fail. Most successful entrepreneurs I know that have had an exit generally were on the 2^nth permutation of the initial set of product features. You keep bashing your head against the wall until you can no longer take it. It is not a glamorous road, and founder depression is very real. Just take solace in the fact that everyone - even the really successful teams - have been where you are. Find a way to take care of yourself and if you are meant to be an entrepreneur, the idea or set of ideas to get you there will eventually find its way into the back of your brain.

Finally - ideas are nothing. Ideas are next to worthless. There are tens of thousands of proven business models you could go build right now if you wanted to. What matters most - whether at your corporate job or your startup - is execution. Make that first dollar, and claw tooth and nail for the second, and the 100th, and the 1000th. One step at a time. No one is 'killing it' and every startup is a hot mess of ego, spaghetti code, and future employment lawsuits.

Just take a breath and don't lose your spark of insanity that impassioned you to build something to solve a problem in the first place.