Eventually all writers face rejection. It is inevitable. You write something; someone else reads it and does not like it. Or worse -- they hate it. Many writers have to face of rejection and that's why they don't write. Others write but do not publish. To them all I can say is you need to face your fears and do both. Writing is about sharing and sharing requires publishing.
Personally, I'm no good at handling rejection. I usually receive it when I try to get something published. I suspect I'm not alone in this and that's one reason self-publishing is so big now. It is one way to minimize rejection, at least from publishers. You still have to face the reviewers though.
My problem with rejection is sometimes I take it too personally. Sometimes I need a day or two to distance myself from the story and see the point being made from the person making the comment. My natural assumption is almost always, the other person is wrong and I am right. Forcing myself to accept the other person is right, especially when he or she challenges a key point in a story is hard. The trick is to try and see how you can be right and the other person can be right too. This sometimes it even leads to a better story. Of course, sometimes I ignore the comments too.
It is fair to say that my first novel is result of rejection. Originally the novel was bigger and had more to it. But based on the rejection I received, I broke it into parts, created a series from it, and focused on what was the first chapter of the original novel.
The result is a much stronger first chapter, which is now a novel in its own right with more to follow. Doing this was hard but I felt it was necessary if I was going to tell the story the way it needed to be told. I also learned a few things in the process so that writing the second novel was easier.
I also have a vague sense that my writing is better, that my creative writing skills have grown and matured, and that I might just be ready to face the horde of reviewers.
So try to keep your perspective and take rejection in stride. Don't let it derail you or make you doubt yourself. But be honest too. If there is merit, even a little bit of it, in the comments, embrace it and revise as needed. It is the only way to get better and the only way to get published.