I would say ignore the nay-sayers and the guys slamming you for your "ego" or just giving you attitude - but do extract the actionable feedback, but only apply that which resonates with YOU. (But now at least you have the other bits that don't agree with you somewhere on your periphery of awareness, in case you turn out to just be stubborn and wrong - but there is no one proven way despite protestations in the comments, and even well validated startup mrthods like focusing on "customer interviews")
I can certainly related to your experience, also solving very hard problems, but I would laugh about 11 weeks as painful as "large amounts of sunk time" is.... We are thinking in terms of years not weeks.
Bootstrapping is almost always the best way to start.
Unless you are lucky, most VC only happens after your success is pretty obvious.
Our solution has been to do dev work for money on the side, one of which resulted in a maintenance retainer. It's a pain in the ass, but has allowed us to work on our startup for almost two years, buying us time to pivot aspects of our bring-to-market strategy or what market to apply our idea to.... In other words, do several BIG pivots.
I would also suggest you decide how to weigh your attention between your products or put them in a sequential strategy that makes sense to you... I don't think you can build three services at the same time at the same level of priority.
If you take the long view, keep pivoting, and keep searching for as much real world customer interaction, your chances of converging on something cool is much improved.
We also got nice growth metrics with very little long term activation/use, which drove us back to do more customer development in the real world (and over skype!)
Keep trying things, keep sharing the journey, we all make many mistakes along the way, hopefully they don't sink a business that "could have" worked.
My view is, you should only fail with flawed ideas, not fail winning ideas due to mistaken models of execution.
Keep learning.