It sure looks like you've been through quite a bit and, at the very least, deserve some brutally honest feedback from this community.

Many may not agree with me and this may not make you feel much better, but after reading your experience, quite a few thoughts came to my mind. In no particular order:

I kinda knew it was going to happen

What? That's a horrible attitude and probably a self-fulfilling prophesy. I know of many cases (mine included) where everything was "perfect", world-changing idea, solid team, great skill, intense passion, practically a perfect alignment of the stars, and it still failed. Software is hard! Startups are harder! You will probably fail anyway, so if you attitude isn't 100%, then you should save yourselves and everyone else a lot of trouble and not even bother.

truly believed that my current startup had potential to grow

See my remarks above. You may have been right about your startup's potential and still failed. This is normal!

I lost the one chance I had

This is ridiculous so just get it out of your head. We all get many chances. Many successful entrepreneurs failed (several times) before they succeeded.

Given that we didn't have any programming or design experience

Then I'm not surprised you failed. Those of us with lots of experience, myself included, are constantly encouraging those with little or no experience to pursue building virtual stuff. It's a wonderful avocation with great opportunity for career satisfaction. But please don't mistake encouragement for approval. You will have to pay your dues first. Sure, it's much easier to come up to speed quickly now than it used to be, but you still have to get something under your belt before you can build good stuff. Like I said earlier, it's tough enough for the best of us to succeed with a startup; by definition, it's tougher for you.

One of the startup advice that I hear most often is to create a product that solves a problem of your own (37signals) because there's bound to be people like you who have the same problem.

There's no guarantee of that. Worse, lots of others may be thinking the same thing, so we end up with lots of teams building the same useless thing that they all want but no one else does. Or others may want, but not badly enough to pay. It's interesting advice that has been effective for some people, but frankly, I've never liked it. As a natural outlier, I would never build something that I want. For me, that's just a recipe for failure. I'd much rather pound the pavement and find out what others want and are willing to pay for.

Please take this advice, like all advice on Hacker News, 37 Signals, or anywhere else with a grain of salt. Our industry is still in its infancy so there are few rules yet, just lots of guidelines. One of the best skills you can have now is to be able to distinguinguish between which advice is good or bad for you.

we sacrificed all the time we had with friends, family, and ignored our relationships for the most part

First of all, that's a bad attitude. Life is a zero-sum game, so by definition, you can't have it all. Using the word "sacrificed" to describe the thing you choose not to have is problematic. You chose A and didn't choose B. Fine. But you sacrificed nothing. In fact, you're probably way ahead. You learned stuff that most others never do, and the people who really matter are still there. By definition, you can't possibly lose real friends by living your life the way you choose. Anyone you lost was never really a friend in the first place.

It was miserable and lonely

Then you're in the wrong business. I spend 90% of my time alone with my computer and I love it! I have figured out how to balance work and life, but make no mistake about it, if you choose to be a programmer, and especially if you choose to start a startup, you will be alone with your ones a zeros a lot. If that doesn't absolutely turn you on, then maybe you should consider doing something else.

still dreaming of get rich quick schemes

Fuck. That. Shit.

If you're doing this to get rich, then please just stop and go do something else. Law school, medical school, Wall Street, selling ebooks, whatever.

I know it sounds counter-intuitive, but in order to succeed with software (and software startups), you must focus on many more things before money. First, you must absolutely love what you do. If you don't, then you will end up writing posts like yours. Then you must have an undying determination to build that which must be built (according to you). Anything less is a sure recipe for failure.

Sure, lots of us get rich but many more don't. And those that do often observe that even though they did the absolute best that they could, the real riches came from sources beyond their control: they got lucky or were in the right place at the right time.

There are lots of great reasons for building the stuff we build. IMHO, "getting rich" is not one of them.

That was the key- it would really tackle the problem of not being able to meet people and just socialize

It sounds like you may have gotten feedback in an echo chamber; that is, you talked to alot of similar people so you thought you had a random sample but really didn't. Frankly, the idea of using technology to accomplish that which is better done without technology (meeting people and not being lonely) is not appealing at all to me. (Previous disclaimer: I am an outlier, so I understand that I may be in the minority.)

This was a terrible mistake that we should've caught on.

Never say "should've". It's not possible to "should've". Now you know. It may not seem that way right now, but that's actually a good thing.

...this was something I had truly believed it, I truly worked hard for and believed that it wasn't just something stupid I created again on a whim.

It was not stupid and was not done on a whim. If it was you wouldn't have gotten as far as you did.

We tried to follow every piece of advice we were given...

Advice is input. Not all input should be processed.

...just had to let out some anger.

Good! Now relax and listen...

You probably won't believe me now, so come back and read this in 30 days...

You are actually in great shape! You have learned things that most people in our industry never learn. Like Edison, you know x ways to not do a startup. So relax, regroup, do something else to feel better for a while, then when you think the time is right, do it again. Use all that you learned to go again without making the same mistakes. There will never be any guarantees, but you should feel confident you will be much better next time.