Moreover, if you have no money left, you will probably want to find a job, otherwise you will become homeless.
But if you still have some money, and it was only just a short sprint of several months with just you and your co-founder, it's good to move on to the next idea.
There is one day I remember very well. I had decided to throw in the towel and start looking for another job. We had been operating in a college town, and I knew the job prospects were poor there, so I took a few weeks to look for a job elsewhere. I was contacted by my apartment telling me I was being evicted. I drove back to get my stuff out and clean up. By the time I arrived, it was night. The electricity had been off for a few weeks, so the lights were out. It was a hot Florida summer, and there was no A/C, so I stripped down to my shorts and using a flashlight I moved my stuff into my car. Then I cleaned it as best as I could by the light of the flashlight. I still remember cleaning out the fridge which had been turned off for weeks, with the bugs in it jumping on my bare chest in the flickering light. I was thinking "This is not my life".
I survived that. You can survive this.
A week later I had my entire life packed into my car and drove across the country to be with my friends who knew me before I had sunk my life into trying to make the company happen.
Fortunately I still had some residual income from another part of the company that I hadn't sold, so I lived off that.
A year and a half in a bathrobe, letting friends pass thru my house, I found myself being asked to help a friend at his startup getting things off the groud, a contract gig, but cash and something back in the working world.
Life continues, its a very hard place to be on day one, but each day it gets better.
It is still an experience that I'd never trade. Ever.
0. You dream
1. You fail
2. You learn
3. You win
Failure was the end of step 1. The only thing you need is a little break though...