It isn’t easy, but it is necessary. Keep in mind that, no matter what stage of writing you’re in, there are always negative things that can occur. Published or not, you can receive rejections on your submission, by editors and agents. If you already have a relationship with them, they’re sometimes kinder in how they reject your work, but a rejection is still a rejection.
Once you’re published, though, you have a track record that follows you. I won’t lie. It helps. But remember that when you’re published your work is out there for more than a few people to look at. You’ll get reviews. Some are positive, which is always a kick.
But some will be negative. Sometimes very negative. Sometimes very negative and posted on Amazon and other sites from which you hope people will want to buy your books. That kind of review, one that can discourage people from trying your work, is always a real kick in the gut.