Allow me to present two truths:
1. No one likes being rejected
2. If you seek to write professionally, you will be rejected.
Bummer, right? It seems every day, on some form of social media, someone is bemoaning a rejection. Not that this is bad- that’s just point number one up there. But, as a writer, you know it’s coming. Even the best of the best, the most well-loved and revered authors were rejected. In some cases, much more harshly than you or I ever will be. So how do you get over it and move on?
It starts, I think, with what’s inside. Artists are, generally speaking, kind of an insecure bunch, particularly when it comes to their own works. So when the work is rejected, that makes it sting that much more. But, as point 2 states up there, it’s gonna happen, so my advice? Expect, revel in it, and just accept that. That’s not to say you’re going to (or should be happy), but do this: when you get a rejection, set a timer of some sort. That’s your time to feel crappy about it. When that time is up, it’s over. Tell yourself to bury it and move on. Or, as the saying goes, hope springs eternal: Have another something ready to submit. Rejection from one place? Fine. I’ll submit something somewhere else. They don’t need you? You don’t need them.
Sometimes there is a silver lining as well- it is a pretty saturated market out there, after all- and most of us are eager to sign the first chance we get, be that for short fiction or some book deal. But how many stories have you heard of someone passing up an offer, and then getting a better one? So maybe the short story you submitted to the place that pays $0.01/word will get picked up by Fireside. Or you pass up a small press and get signed to a big one. Step back from the rejection, and look at the big picture- maybe they did you a favor.
Speaking of the big picture- there is simply so many people submitting to so many markets, you’re going to get left out sometime. Your work might still be fantastic, but those are the numbers. Besides, would you really want everything you wrote to be accepted? Sure, the paydays would be nicer, but what motivation would you have to improve? Would readers want all you, all the time?
So- take it in stride as best you can, and be the best writer you can and it will all (probably) work out.