2.) Get feedback from your customers (i.e. you need to find out asap if they will use, or better yet pay, for your product).
If you hear the words "interesting," "cool," or "maybe" in their feedback; something is wrong with your idea. There's no product market fit.
If in your conversation they ask you how much does it cost or how do they sign up, then you might be on to something. This is what's known as a "win." A "win" doesn't necessarily mean you've struck gold, only that you might be digging in the right area.
Your goal is to accumulate as many of these little "wins" as possible to stay alive and ensure you're working on something somebody somewhere wants.
Good luck! Sounds like you're on the right track!
Become an expert in your industry. Work harder and longer than anyone else. Take breaks once in a while.
Wake up and do it all over again until you become big.