Kind of like a plan that starts with "first make a viral youtube video then...". That first step is significantly larger and more difficult than it seems, and kind of sounds like that is your experience.
If I were in your situation, I would prioritize the quickest path to stability. If your e-commerce business is popping off, drop the startup. If neither of those are going anywhere, get a job. Without having some stability it will be difficult to take another swing at your startup.
Once you are treading water again, I would re-evaluate your startup strategy. I wouldn't write any code, or build any prototypes yet. First step is getting in front of people who are your target users and ask them lots of questions about their problems. If the idea you are showing them isn't doing it, ask about their other problems. Build the lowest effort thing that solves that problem in the happiest case and keep showing it.