Okay, seriously, the first thing you need to do is step away from that thought, slowly. Go ahead, step away. It’s going to be okay. - I mean it. Really. It’s going to be okay.
Rejection is not deadly. It just feels that way. You’re a writer and if you, well, write and send your work out, you’re going to be rejected at some point. It won’t kill you, I promise. It will hurt like hell, but it won’t kill you.