Write a postmortem.

Get everything out of your head. Stream all the bullets that come to mind. Your mistakes, your feelings, all that will come out.

Startups are supposed to fail, and it happens all the time. You might cry, but you have to write down a postmortem, and get closure, fast.

Ask people who were involved in your business on sidelines about their vantage point. What do they think went wrong?

Was there any advice they gave you that you did not follow? Was there any information or feelings that weren't shared in due time, which could have helped the situation?

Be open to any honest advice. You have to want to hear their authentic thoughts, not a confirmation of the narrative that you want to believe in.

Don't make big life decisions right away. Take some time off and do something else.