It depends. If you have enough savings, you can take the much needed time-off and clear your mind and then work on another problem to solve. If money is the issue then get a consulting or freelancing gig (plenty of info on HN how to get 1). Write a guest blog post on why your Startup failed. Also there are plenty of people looking for Co-founders. The worst mistake is to not start something new because you think you may fail again.