Why are you writing? If it is solely to get published, quit writing. Now.
If you write for any motive other than the desire to create art with words, you may as well put down your pen.
Unless you are already published, your odds of commercial success are low at best. Making any large sums of wealth is improbable. You’ll likely spend more of your own money in time, supplies, editing, mailing, possibly self-publishing. I know, it’s backwards. The difference between you and [insert author whom you admire here] is that s/he caught the eye of the right person at the right agency in the right moment. You can’t control that kind of timing.
Not everyone thinks they can paint, tattoo, build, compose, design or any of the hundreds of ways people can create art. Almost no one makes clothing anymore, let alone has the knowledge to sew. We have far more lawyers than poets. So why does everyone think they can write?
There is a notion that writing is easy. Everyone thinks they can write simply because they “write”. They learned the alphabet, cursive, basic grammar. They write emails and checks and business documents. Writing (read: “computering”) is what 21st century humans do.
What separates the artistic or revealing writer from everyone else is the passion to tell your story, even if no one wants to read it.
You’ve written everyday for most of your life. You’ve forgone sleep for just one more chapter. You play with dialogue and stanzas and possibility until your mind is numb. You’ve been told you have a great story, your beta-readers devoured your manuscript and your editor thinks it is a sound piece of work. Yet ever day you open your mail and your email to find rejection after rejection.
Sure, it is disheartening; validation is what gives recognized or monetary value to anything. But you are a writer, and you promised yourself you would write no matter what. Failure is relative. You have 90,000 precise words in a fat manuscript. You have poured years and energy and health into your story. You’ve made every attempt to network and be seen and yet the rejections keep coming. So what. That last step does not make your endeavor a failure.
Having the fire of language inside of you and never putting words on paper is the only true failure and you’re so far beyond that you’ve already succeeded.
Focus on the future. Keep sending queries and handing out your specs. Write the next installment. Heck, start a whole new story! Write because you have to write just like you breathe because you would otherwise die.